D&D 5E Turning a boring trap into an exciting encounter.

[DMSage]

​

This article will teach you how to turn traps into exciting encounters/puzzles by themselves.
In my last article I discussed why to use better traps and some of the biggest problems with traps. Make sure you read it before reading this article or you will be asking yourself why you'd put all this extra work in when you could just have a ten second trip wire trap based on a perception check (Problems with traps). Now it’s time to discuss how to make fair, high quality traps that engage and challenge players.


First, a reminder of what we want our traps to accomplish:

• Finding traps should not be based solely on luck/dice rolls
• Random trap searches shouldn't slow down the game
• Solutions require character’s skills, feats, and backstories to highlight character individuality and roleplay
• Players (as well as their characters) should have choices to make and puzzles to solve

Solving engaging traps are part player decision making, part character build, and part luck. Usually in that order.


[h=2]Designing quality traps[/h]There are six steps to designing the mechanics, purpose, and solutions of a quality trap. Keep in mind that as you get better at this, you will not have to go through every single step and can instead skip to the parts you know are relevant. This guide is meant to be used as a reference. Not something you follow from start to finish every single time.
[h=4]Step 1: Give the trap a story and a use.[/h]It is not enough to have a “spike trap”. Traps must be further defined in order to make them interesting. Asking yourself the following questions will help you to define your trap.

• Who made it?
• Who was it made to stop?
• What kind of trap is it?
• How do the creators of the trap avoid triggering it?
• Has this trap been triggered before?
• Why use this trap in this location?

[h=4]Step 2: Design trap components and solution.[/h]With the basic purpose and background for the trap in place, we can proceed to designing the trap’s mechanics and solutions.

• What triggers this trap?
• What does the trap do when triggered?
• How is the trigger connected to the mechanism?
• What mechanically or magically needs to happen to make this trap run?
• What is needed to hide this trap?
• What are likely ways to “solve” this trap? (avoid, disarm, safely trigger…)

[h=4]Step 3: Identify your starting clues[/h]The players are chasing three goblins who have a magic artifact. The goblins run across a rope bridge suspended 500 feet above lava. The lead character gives chase. Thirty feet out the weakened bridge snaps and that character falls to his death.
Does that feel fair? As a DM I have a rule: “A quality trap is one that can kill my PCs and the players will not be angry about it.” In other words, the trap should have enough of an opportunity for my players to solve or avoid it that if it happens to be the cause of their death, no one will be too upset. The bridge example is completely unfair. Sure you can argue that it’s his fault for going out, but again, the players don’t see what the characters see. At this point, the player isn’t playing the game against clues or logic, instead he’s just wondering, “Is my DM a dick... enough to kill me here?”.
The players are chasing three goblins who have a magic artifact. The goblins run across a rope bridge suspended 500 feet above lava. The lead character gives chase. As he runs up to the bridge he notices the ropes on both sides are completely frayed with only a few strands holding them together. The strands look as though they were cut through by dull blades. A couple of strands snap under just the weight of the goblins.
This time if the player chooses to walk across the bridge, he would probably be met with four other players yelling at him, “don’t go!”. In this case if he dies, he will probably feel more stupid than mad. I am not saying this is a good trap, but it’s an example of players being given more sufficient warnings. In my opinion, these warnings should be clear and well thought out. Here are seven types of clues you can use to alert your players to danger.
1. Sensory cue
This clue uses one of the five senses to show the players danger. Sight, sound, touch, smell, or taste
2. Encountered previously
Show an already triggered trap that lets the party extrapolate clues to spot a later trap.
3. Emerging pattern
Show a series of trap types or placements that have a clear pattern for the party to recognize.
4. Obvious location
This perhaps is the one time you don't need to give a clue of the trap itself. A gold plated chest sitting on an altar is just something the party should check. Maybe give them a freebie on the first one of the campaign, but the party should know to check treasure chests, secret doors, and scroll cases without you telling them.
5. Sixth sense
Feeling arcane energy isn't a real sense but it can work in the fantasy context. You could also use intuition of a rogue or a dwarf’s knowledge of stone to give him a clue that something isn’t right even if they haven’t consciously identified the clue yet.
6. Told or shown the location
Someone points to the spot on a map or tells them that the front door is trapped.
7. Show one trap component
Show them the trip wire but hide the spikes well. Show them the next 40 feet of floor drop out, but the lever to stop it is in another room. Show them the glistening magical field, but let them struggle to find out what it does and how to get past it.


[h=4]Step 4: Identify the skill check components.[/h]This is one of the most important steps of constructing a trap. It allows you to give the players a puzzle to solve while still allowing the rogue to feel special for taking training in certain skills. In fact it will make everyone feel unique about the skills they chose.
First I need to mention how skill checks work. This is a topic for an entire post itself, but it needs to be brought up here. A character in the game should have human or above human perception. Everything that is likely to be perceived should be immediately described by the DM. The obvious is not what skill checks are for. Skill checks are for noticing or figuring out the extremely difficult but possible things. Seeing the stab wound should be automatic, no skill check needed. Seeing the blackened, swollen skin around it should be automatic, no skill check needed. Determining what kind of poison was used to cause this type of wound, that isn’t something you can just see or know. That would make a great nature or medicine check. The same applies to traps. Make pieces of the trap visible to the players. If they investigate, tell them exactly what they see. Do not make players roll to use their eyes. Investigating automatically shows them what is there. This step is here to help you design the less obvious and difficult skill checks.


Most of the skills you will call for will be based on the information you gathered in steps one and two. Using this information you will be coming up with a list of things the players could notice or try to do with the trap that require skill checks.


One way to develop these clues and maintain each character's individuality (have to make that rogue feel special) is to differentiate amounts and types of information. A example of this is with a magic trap such as a ward. The wizard, an expert in magic, will be able to make an arcana check to try to determine the type of ward this is, what it does, and maybe even try to disarm it. He can get a direct answer and maybe even a solution. The rogue on the other hand, who is skilled in mechanical traps, but not magic ones could still make an investigation check and be rewarded for being a master of traps. In this case he will get information such as, “You can tell the trap is powered by something you can see inserted into the wall but that you cannot reach. It's not just a spell that was cast and left, this is more permanent." This really allows each character to shine in the areas they chose to maximize. The wizard gets wizardy information and the rogue gets roguey information.
I will have a list of traps in the next article as examples.


[h=4]Step 5: Make traps harder over time[/h]Instead of thinking of a trap as a single trap or single puzzle, all of the traps should be thought of as one giant puzzle. This allows you to "give up" a few traps as foreshadowing . You have to be okay with a few of them not getting triggered. The trade off is that you get to make your later traps much harder and deadlier, relying on the players to have picked up all of the clues and foreshadowing you’ve given them along the way. Just like any good video game doesn’t throw you at the boss to start the game, you should not throw your characters at traps that they cannot find or solve. Traps should progress in difficulty level. Here are five ways to make your traps more difficult:

• Remove a clue (keep a minimum of one)
• Take away a sense (too dark, too loud)
• Prevent the most obvious solution (too long to jump over)
• Increase the trap’s complexity
• Add an additional challenge that prevents proper solving (fight, NPC distracting them)
• Add a time limit

[h=2]Running quality traps[/h]By now DMs should have a well planned out trap complete with parts and checks that can be made to solve it. Now it’s time to throw that trap into the game and manage it in real time as the players do unexpected things. This is the art of DMing.


[h=4]Step 1: Give the clues[/h]You have to actually give the clue to the players. You can try to work it in naturally, but should always err towards being obvious. It’s better to give a clue clearly and directly. It is also important to remember that players only have the clues that you give them to work with. If you give them one clue and they can’t solve it using that clue or have one bad roll, then their leads have run dry and they have nothing else to work with and no choice but to walk right into the trap. I suggest giving them multiple clues, some with clear solutions and some more difficult. This way, when the party screws up one clue, they have two other, more difficult, leads to follow. Each time they fail at recognizing or solving a clue, the trap becomes more difficult to solve safely.


Important Sidebar
I have to take a moment to talk about metagaming here because this is where I see it called out the most often by DMs. When a DMs makes a poor traps, such as a spike trap that the party can just walk around, and they really wants the party to interact with it, they will use “metagaming” as their tool. First, they give no clues that the trap is there, forcing the characters to hit it. But this feels unfair, so the next time the DM gives a vague clue like mapping out this section of the 50 miles of forest they were walking through to let the players know something is up. The player’s thinking: “why would he show us this 20 foot section of 50 miles of forest now? Either a fight or trap is coming.” So of course the players say, “Perception check”.
Here is the metagaming cheat for the DM. If the player passes this perception check then it is okay, the DM lets them pass this trap. They see it and walk around. If the check fails, the player knows that he didn’t get a high roll and knows the DM stopped them here for a reason. The player knows there is a trap and wants to roll again or have another player check. The DM, worried that they will find every single trap if he allows this, says, “no, that’s metagaming, you are the rogue and you searched and think you did a good job. So you have to pretend like you think you did a good job.”
This is a cheap trick and why I advocate making most puzzles for your players to solve, not your characters. I know it’s a role playing game, but it’s also a game. If your player solves a puzzle, then the character solves it too. Quality traps have multiple solutions, are placed in good locations, and are run well in game. This means a good DM can give away the location of almost all of his traps and still have satisfying interactions with them.
Some people might be confused about giving away the trap’s location so let’s look at one example and I will give more in the next article. The party finds a gold laced chest that is locked in the boss’s chambers. The party assumes it’s trapped.
Rogue: I’ll make an investigation check. (rolls a 2).
DM: you search over the chest but the lid is sealed up tight so you can’t see between it. There appears to be nothing on the outside. You would guess that a chest like this is trapped but if it is, the trap mechanism must be inside it or magical.
Rogue: I want to check under it to see if there is a pressure plate or something
DM: The chest has four feet that lift it up. You can see under it, no need to roll, you are sure there is nothing under there.
Rogue: I’ll take the chest into the other room where it’s safe and bring the rest of my party in.
Rogue: "Hey wizard, come take a look at this."
This is where most DMs would say, “metagaming! You already searched it for traps so now you just have to open it or leave it.” This is dumb.
Wizard: I go over and look for traps.
DM: make an investigation check.
Wizard: (18)
DM: You search the outside of the chest and just like the rogue see no signs of a trap trigger. However, while touching the chest you feel a soft arcane presence surge through your hand.
Wizard: Arcana check (17)
DM: You sense a magic ward placed around this chest that would trigger if opened.
Wizard: I’ll cast dispel magic on the ward.


Rogue got to figure out why he failed (because it was an arcane trap), the wizard got to feel like a badass (because he solved a trap), information was given to them freely, metagaming cheat was not used, and fun was had by all. Now the question is, how do traps ever get triggered? This is where step three comes in. But first:


[h=4]Step 2: Adjudicate solutions[/h]I’m not going to write a lot in this section because there is a wonderful article on this topic already from The Angry GM called "Adjudicate Actions Like a Motherf$&%ing Boss!". I’ll just put some of the important steps here and then link to this amazing article. This process starts after the DM has described the clues to the players and they decide how their characters respond or what actions they take.

• determine exactly what they are trying to do, and how they are trying to do it
• determine if it is possible
• decide if it needs a dice roll or automatically fails/succeeds
• roll dice or have players roll dice
• decide on and describe the outcome
• identify positive and negative consequences

This information is mostly summarized from the angry GM's site.. Go support his site! He is the main influence for me to make this site.


[h=4]Step 3: Find other ways to trigger the trap[/h]Since this approach means a lot less traps will be triggered, we need to do some modifying of how we run them in the game. Now that we have better quality traps that are more interactive with scaling difficulties, it will be ok for players to trigger less of them because interaction with them is interesting by itself.
Some traps, however, will still not be exciting if located. For example the basic rope triggering a falling spikes trap. Once the party sees it, it's solved. Now we will look for other interactions that can happen with the trap. Here are four ways for this to happen. Keep in mind that the consequences you come up with when adjudicating trap interaction will help you to identify opportunities. (for example: party left the chest on the pressure plate and decided to rest before disarming it. An angry kobold who escaped earlier sneaks back in and kicks the chest off the trigger and tries to run away)
A few broad examples:

• An enemy triggers the trap
• Added layers of trap difficulty
• Players can reset or use the trap against enemies
• Distractions (it’s hard to disarm/find a trap while fighting or running away)

[h=4]Step 4: Adjust difficulty[/h]The last stage in the process is to adjust the difficulty of the traps. If you have a group that is just not noticing your clues, it is likely that you are making them too hard. Move away from the harder clues and give them more clear clues like “you see a wire pulled tight across the ground”. Start making your clues more visible or add in easier clues to help your players. Once they start to get the hang of it, you can adjust the difficulty back up.


Here are a couple examples of traps I made using this method Encounter traps

 

[iserith]

I groaned at the assumption that players are asking to make skill checks while the DM assumes their actions during adjudication. That's backwards in my view.

But on the whole, this is a good article. Nice job.

 

[DMSage]

I groaned at the assumption that players are asking to make skill checks while the DM assumes their actions during adjudication. That's backwards in my view.

But on the whole, this is a good article. Nice job.

Agreed, I usually don't like it when that happens and encourage my players not to. I just taught a new group of people how to play and I made them put their character sheets away until I called for the first check so they would get the idea.

 

[Celebrim]

Overall, a very good article and indeed one of the best quality essays written on EnWorld in the past couple of years.

I have some minor quibbles, but please don't let my criticism in any way get in the way of that first sentence.

First, you write:

Make pieces of the trap visible to the players. If they investigate, tell them exactly what they see. Do not make players roll to use their eyes.

Now I agree absolutely that players should not have to roll to use their eyes. Indeed, they should not have to ask to roll to use their eyes or any other sense. That sensory information should be coming to them all the time, and whenever it matters the GM should be making passive checks on their behalf to see if they notice even the fine details of the environment. You shouldn't as a player have to ask what you perceive. You can ask to investigate something more closely - either by spending more time looking at it, getting closer to it, or touching and exploring it - but you should expect to receive whatever sense information your character could observe automatically.

But it can be the case that a trap has no obvious sensory information. Consider the case of a tripwire made of some semi-transparent sinew ideal for making tripwires viewed in less than perfect light, amidst any number of more obvious sensory queues. There is no reason to suppose that this tripwire gives off any sensory cues that don't require above average perception. Thus, by the rule that you don't have to ask to roll to use your eyes, there should be a chance that highly perceptive persons will passively observe the tripwire by some means. This chance might be very low, but it should be there. Then, whenever the players act warily and investigate, there is a new chance - perhaps and increased one because they are wary and not distracted - that they observe what was subtle and unseen before. Likewise, if the player employs some stratagem to get new sensory information, the DM adjudicates that, either as an additional favorable or unfavorable chance to observe the hidden information, or else as straight delivery of information that is obvious.

Again, returning to the example of the tripwire, we might write/read/invent something like:

"The stone door opens to reveal a square passage, about 8' on a side bored straight into the mountain. The passage disappears into shadows about 60' ahead, outside the range of your light. The floor is fairly smooth, but still bears the chisel marks wear the stone was hammered away. The walls have been more finely shaped and covered with a thin layer of plaster, which in places has ran off the walls from moisture damage. The carving show a jungle montage of plants, serpents, parrots. Skull faced warriors with bladed clubs leer out among the foliage. The walls were once painted in bright colors, but these have faded, or pealed away, or else been ruined by spreading mold."

Now, obviously there is lots of additional information that the players can gather here by stopping to inspect things. But less obviously, 20' down the corridor is a difficult to detect tripwire which at this time the PC's have failed to detect through some combination of bad luck, lack of perceptive skill, distance from the thing to observe, inattention to particulars and the subtly of this fact. Perhaps each had only a 5-10% chance of noticing it right away.

The PC's, being no fools, don't rush up the corridor. The recognize from the color of the situation that traps are likely. Instead, they may propose any of the following:

1) "I begin to slowly explore the passage, taking care to slowly wave my light source up and down to bring out any features of the floor I might have missed."

This is essentially requesting a more active search of the floor ahead, and should be rewarded with an additional attempt to notice the tripwire before blundering in to it with the best of chances. The person is attentive to the floor, and taking steps which would naturally highlight the presence of the trip wire. There is still a high chance the near sighted absent minded wizard with no perceptive skill might fail to notice what is right in front of him, but the highly observant rogue now has a good chance of noticing.

2) "I crouch down and pick up some dust and carefully lightly sprinkle it ahead of me, while carefully moving the lantern in my other hand to look for shadows and features I might have missed. I repeat this procedure every few inches as I progress."

In D20 terms, this a 'take 20' sort of proposition, explicitly or implicitly. Moreover, because its explicitly looking for the sort of things that might give away a trip wire, I'd probably give it a circumstance bonus to find the trip wire. Even if the trip wire is hard to find, I might well allow this one to be automatically found. But even with such precise intentionality, if the thing to be observed is even more subtle than the proposed trip wire, it might be the case that the near sighted wizard with no skills invested in perceptiveness fails to notice the thing despite his best efforts.

3) "Taking my staff and walking slowly, I begin gently probing ahead of me as I advance down the corridor"

One thing is now almost certain: it's the staff that touches the trip wire first, and not the player. So the player probably has at worst a 5' separation from themselves and the trap, whatever it does. Depending on what it does, that may mean the staff is effected and the player completely escapes. Moreover, since this employs a new sense - touch - at the very least another chance of detecting the trap out to be allowed. The question now becomes, is the players sense of touch fine enough that they can feel the trip wire before they actually trip it? Again, I'd tend to resolve this being highly likely to reveal the trip wire, likely with a circumstance bonus to find a trip wire because of the highly appropriate action. Failure here indicates your felt the staff impact the wire, but noticed it to late to avoid triggering it. In the case of a localized scythe trap or a falling block trap, the fact the we know your staff is in front of you means you probably avoid damage entirely (the staff may or may not, though).

4) "I get down on my hands and knees and place a bit of straw between my lips so that it lies on my tongue. I then go forward lifting my head slowly up and down and gently manipulating the straw with my tongue."

This is a very specific real world technique for finding a trip wire without setting it off. Regardless of the characters perceptiveness, he's going to find a trip wire given enough time spent on the problem. I'm not going to get into a table argument with a player being this specific about his purpose. This is a good example of not needing to roll to tell the character what he finds. Note though, this search is specific only to trip wires. It's not the same as having +10 search/perception skill, which is going to notice lots of things this technique does not - the technique isn't helping much against pressure plates for example. In theory, a player could describe all the various detailed routines that the character goes through to search an area and in theory automatically find lots of clues that otherwise might only be available to a perceptive character. But at the least, I would penalize a party acting in that manner such that it would take 10 minutes to cover 5' of passage, as the imperceptive character would in no fashion as efficiently observe the environment as one with great perceptive skill. I would probably also penalize a player pixel bitching in this fashion by counting them as distracted and imposing a penalty on observing everything but what they are focused on, in a way I wouldn't penalize a PC with high ranks in perceptive skills. Because seriously, while this sort of puzzle solving is fine when appropriate, if that was happening all the time, it would be annoying.

Note that although I accept all the above exacting propositions as valid, I'd also accept a game proposition like, "I take 20 to search the corridor as we advance down it." Such a proposition is clear in its intent and shouldn't be penalized. And in general, it doesn't require I nail down hard what exactly that looks like. On the other hand, what I don't do in that situation is give any special advantages in fictional positioning that might come from a more concrete proposition. On the other hand, you have no assumed disadvantages either. It's a good idea though to establish whether a search is a visual inspection only, or whether the person intends to touch the object. I tend to assume search is also tactile unless otherwise stated (and apply a penalty if the person wants to keep their distance).

This is where most DMs would say, “metagaming! You already searched it for traps so now you just have to open it or leave it.” This is dumb.

I sincerely hope not. One of the biggest ways to avoid this problem though is to make the DM responsible for all rolls involving perception. It's important that the PCs not be able to determine whether they didn't find anything because of a low roll, or they didn't find anything because there is nothing there to detect. Any meta-gaming here by the Rogue's player is solely do to the Rogue's player knowing he rolled a '2'. If he doesn't know what he rolled, then its purely due caution. Speaking as a long time 1e Thief, the 'Find Traps' check was so unreliable, that any good Thief resorted to it only as a last resort as a safety check to make sure you the player hadn't missed something in your due diligence. It's never metagaming for a player to be cautious when they legitimately lack information. Of course people in a trap filled dungeon exercise due diligence and check everything at least twice. It's only meta-gaming when they act on something that they should not know in the game world.

And DM's should never call it 'metagaming' when a player attempts to interact with the environment. Interacting with the environment is what you want to happen. Don't punish it.

When a DMs makes a poor traps, such as a spike trap that the party can just walk around, and they really wants the party to interact with it, they will use “metagaming” as their tool. First, they give no clues that the trap is there, forcing the characters to hit it. But this feels unfair, so the next time the DM gives a vague clue like mapping out this section of the 50 miles of forest they were walking through to let the players know something is up. The player’s thinking: “why would he show us this 20 foot section of 50 miles of forest now? Either a fight or trap is coming.” So of course the players say, “Perception check”.

Even though you correctly point out the problems of a DM wanting traps to be triggered, I feel this is by far your worst passage, because there is so much wrong with this and you don't call it out. First, it's not unfair to just be informed that you stepped on a spike trap while walking through 50 miles of forest, provided the DM gave a chance for the player character to passively notice the spikes through some mechanism. I think what is probably unfair here is that 3e unfortunately made traps only detectable through active perception, and didn't have some default passive level of search. This implies - again unfortunately - that no trap can be detected if it isn't actively searched for, which I think we both disagree with in our own way.

Secondly, the player shouldn't have to say, "I'm looking at this." The DM should make that check on his own before determining pass/fail, whether the trap was triggered.

Thirdly, you should never ever map a 20x50' section of a 50 mile forest. This should be theater of the mind until the actual fictional positioning of the party relative to something matters. There is only one thing here at present, a spike they either stepped on or didn't. We don't need to know where everyone is standing relative to that.

But most importantly, what makes this scenario bad is that it is pointless. It doesn't make for an interesting scene whether they notice the trap or step on the spikes, because the trap is disconnected from the environment. It's a pointless hit point tax. What would make this scenario interesting is that in fact there is an area of the forest liberally salted with these punji sticks, that have been placed here by some mad cannibal hermit or an ogre magi or a tribe of goblins or a VC ambush or whatever and this initial interaction is how we are introducing that scenario and setting apart the long overland journey from the more tactical play beginning here. In other words, if we use this simple and not terribly dangerous trap to begin framing a more significant scene, then that's a good thing.

What makes a trap particularly well designed is if it creates an ongoing situation. Traps at hit point taxes/fines aren't always bad, but without time pressure or surrounding context you shouldn't even bother with them because the solution is rather trivial. There isn't a puzzle introduced by the trap.

 

[Kabouter Games]

Subscribing for future reference and thoughts.

 

[Saeviomagy]

Mostly good, but I think it falls into a typical bad assumption about traps: that they are only 'succeeded' at by totally bypassing them with zero resource consumption, and therefore the main design decision of a trap is to work out how to reveal it to the players without it hurting them.

We don't treat combat that way: typically adventurers don't expect to see combat coming from sufficiently far off that they can totally negate it's impact upon them, and once they engage in it, they expect to consume resources. In fact, the more resources it consumes, the more heroic they feel when they succeed.

The ideal trap is one that consumes resources and makes the party work together to resolve. That resolution does not necessarily mean the trap is disabled: merely that it didn't kill the party or stop their progress towards a goal.

 

[Misty]

pretty cool, i'm definitely using this in my campaign

 

[Imaculata]

The ideal trap is one that consumes resources and makes the party work together to resolve. That resolution does not necessarily mean the trap is disabled: merely that it didn't kill the party or stop their progress towards a goal.

No, I think the ideal trap is one that creates suspense, and a fun story, while also providing the players with important choices. Resources are irrelevant in my opinion.

If the players run into a trap, and there's a tense scene where they try to disable it and yet they come out completely unscathed, then that is fine. There was excitement, and their clever thinking prevailed.

But what does matter, is how they can interact with the trap. If it simply requires one dice roll, then that is not very engaging. Take Iserith's trap for example: There's a hint of a trap, in the form of an arrow, but the players must figure out where the arrow came from to find the trap. Once they find the trap, what happens next?

Often a player will say "I disable the trap!", but most DM's then simply ask for a roll, instead of asking "How do you disable the trap?". It all comes down to storytelling in my opinion. If the player just rolls to disable the trap, then all suspense is gone. The success relies on a random outcome, rather than an important informed choice.

But if the DM asks the player how he will attempt to disable the trap, the outcome is now uncertain, and there for there is suspense. Depending on how the player chooses to go about disabling the trap, it may still require a dice roll, if the DM feels the outcome is uncertain. But the key to designing a good trap, is making it exciting, and providing options.

 

[psychophipps]

It's also important to keep in mind that traps work well when coordinated correctly. There is no set rule that the trap has to be sprung right when you walk into it. What if the orc lair had spike traps that only activated after an ambush was sprung once the PCs are passed them to cut off maneuver and/or escape? Put another one right next to that handy-dandy pile of crates and barrels that intruders will likely maneuver to for cover from your crossbow ambush.

Always keep in mind that even Orcs have better things to do than get dead and will be as mean and nasty about keeping up the whole breathing thing as any adventurer...

 

[Imaculata]

Another clever use of traps, is allowing the players to use them against your monsters. I often place traps in places where they could possibly also be useful to the players, so that "not disarming the traps" is a viable option. This is assuming the monsters don't know about the traps of course.

I once gave my players a map of the dungeon, that had all the traps clearly marked on them. It was then up to the players to take out a group of monsters that clearly outnumbered them. The players went about luring their enemies into the traps on purpose, which was a lot of fun for them.