Hey everyone. I am a new DM, about to set up a couple skill challenges for my players (the game is this weekend) I have never set up a SC before so I wondered if anyone could give me advice or help on how to approach this:
SC#1: The player characters are accused of a crime they are not guilty of (the town guard has confronted them), but the town guard is already bogged down enough, so the captain of the guard listens to their defense, and depending on how convinced he is, they are either let go so he can deal with other problems, or they are placed under arrest and must then escape from prison and hide form the law officials while in town.
These seem to be two challenges, in fact, the second only happening if the first fails.
"Interrogation":
The guards state the accusation and ask questions. You might want to prepare some of the possible questions they might ask to create a natural flow of the interrogation. When the PCs choose an answer to a question, figure out the most appropriate skill. Note that the Captain and his guards will want answers from everyone, so each PC will have to make a check by default. Some ideas:
Interrogation
Complexity 2 (6 successes before 3 failures)
Insight (Moderate DC): The PCs try to read the situation. On a success, it becomes clear that the Captain really wants to get over with this, and they should hurry. This grants no more than one success. Alternatively, hey can also read the direction they need to take the interrogation, granting them a +2 bonus to their next Diplomacy or Bluff check.
Bluff (Moderate DC): The PC tells a lie. Can be used to gain up to 4 successes.
Diplomacy (Moderate DC): The PC tries to clarify the situation and put their actions in a better light. Can be used to gain up to 4 successes.
Diplomacy (Hard DC): A PC can attempt to answer for another PC. This can grant up to one success but any number of failures. The Guard Captain doesn't generally like it if someone else then the asked person answers, but he likes to know who is in charge. (The PCs will use this option if one of them is really terribly bad at social skills compared to them.)
Streetwise (Moderate DC): A PC can bring up a witness or someone that would vouch for them. Can grant up to two successes. The guard captain really doesn't have the time or inclination to verify this, but he will keep a "mental note".
Failure: The Captain decides to take the PCs prisoner. They can decide to run now or escape the prison later, which will open up a new challenge. (No XP gained for failure.)
Success: The Captain is convinced enough to let them go.
I think the DMG does have an example on a chase, that should be re-usable, probably as a Complexity 1 challenge.
Escaping the Prison (Complexity 1)
My basic assumption would be that escaping the prison is not a
Prison Break (TV show) scenario, but more a "create a momentary diversion and run."
Intimidate (Moderate): Force another prisoner to help you in your plan. Can be used to gain up two two successes. (But no more than prisoners available.) The PCs can keep using this skill to get more prisoners on their side, which might be helpful later on.
Diplomacy (Hard): Convince another prisoner to help you in your plan (and not sell you out.). Can be used to gain up to two successes. (But no more than prisoners available.) The PCs can keep using this skill to get more prisoners on their side, which might be helpful later on. It is harder to "diplomance" the prisoners, since they are distrustful of each other and everyone is looking out for himself. Succeeding on a check grants you a +2 bonus to your next Diplomacy or Intimidate check, too.
You might also allow this skill to be used on a guard.
Streetwise (Easy): Recall details of the prison guard and the prisoners to anticipate possible reactions. Can be used to gain no more than 1 success.
History (Moderate): Recall "famous prison breaks". The DM might use a succesful check to give clueless players a tip, too. Can be used to gain no more than 1 success.
Bluff (Moderate): Trick the guards, maybe by someone pretending to be ill, offering some rewards, claiming that you have some vital information. Can be used to gain up to 4 successes. On a failure, any further check worsens by 2 points.
Thievery (Hard): Manipulate the lock. Can be used to gain up to 3 successes. The lock is open on the 3rd success, but the PCs still need a distraction.
Success: The players overpower a guard or convince him to help them, and can go on with the Case scenario.
Failure: The cell door is open, but it's chaos - the guards are alert, the prisoners are fighting amongst each other. Pick an easy encounter (XP value equal or less than the challenge) against the PCs, possibly with one "normal" creature and a lot of Minions for extra guard forces. Any intimidated or befriended prisoners add one Minion (Human Rabble?) to the side of the PCs.
After the combat is concluded, the chase challenge begins.
Note that the prison break, the possible prison fight, and the chase (and any ensuing combat due to failures there) should all be considered "1 encounter", meaning the PCs do not regain encounter powers nor can they freely spend healing surges, so the encounter overall will be harder than it normally would be.
SC#2: A local Noble has detailed info on a location the PCs are looking for, but he does not know the PCs, and is a little stuck up and will not easily give out info. I figured that if the PCs had been in prison and had to make an escape (through a sewer system) that they would be smelly and dirty, making the noble even less impressed with them. If they succeed this SC he gives them a map detailing a safe route to the locaton. If they fail, he will begrudgingly give them the location, but verbally only, and it is up to the PCs to find their own path (which will lead to a combat encounter as it is a dangerous area).
I would make the Diplomacy DCs either harder or apply a penalty to them if they had to run from the prison. Intimidate attempts wouldn't get any harder for the PCs being dirty.

You might allow a lot of "Insight" uses in this scenarios - the Noble doesn't forgive slights easily, and it is important to understand what makes him tick before asking him anything.