When I and some other DMs use skill challenges, we have the skills we think would be primaries picked out, as well as secondaries. We don't tell the players they are in a challenge, we just roleplay the scenes. If a player does something roll worthy, I tell them to roll and make note of the result. If a secondary or non listed skill is used in some form of awesome that makes sense, I will treat it as a primary.
I also like skill challenges to be larger than a single encounter, with maybe a battle in the middle, and certain features of the battle affecting the skill challenge. Example, evacuating prisoners before concluding a battle would count as a success, not doing so would not be a failure. Allowing a prisoner to be killed during battle would count as a failure.
Yes. I have had skill challenges that stretched over
three sessions, because the party is doing other stuff at the same time. I have had skill challenges in the middle of a combat, skill challenges the party abandoned without succeeding or failing out, multiple different skill challenges at the same time, etc.
I disagree with both of these premises.
(1) The creation of a skill challenge (esp. when created as part of an adventure, rather than on the fly) implies a decision ahead of time as to how the encounter will be approached.
In a poor skill challenge, this may be true, but a good skill challenge might read something like this (spoiler blocked on the off chance one of my current players takes a look at this thread, as they spent part of last session with it and aren't done yet):
[sblock] The pcs should be able to hire a boat to take them out on White Lake for a couple of gold pieces, but the island itself is cloaked by a combination of illusions and weather magic (cloaking it in fog). In order to find it, the pcs must defeat this magic by completing a skill challenge.
RUNNING THE SKILL CHALLENGE
Finding the island is a level 11, complexity 3 skill challenge. To successfully complete it, the pcs must achieve 8 successes before 3 failures. Once the pcs get close (after they have achieved 5 successes), see Complications, below.
Since a combination of illusion and weather hide it, the pcs' possible approaches to finding the illusion include the following:
Search Grid: The lake is truly too large to divide and search without immense manpower, but the pcs can spend six hours to eliminate everything within a few miles of the Delphinate proper. Doing this doesn't require any skill checks or gain a success or failure for the party, but gives all further checks in the skill challenge a +2 bonus.
Pierce Illusions: A character that expresses the belief that illusions are involved may attempt to see through them with an Insight check (DC 27). Success means that the character earns a success; though they cannot see through the veils of mist, they can make out which ones are illusory. Failure ensnares the characters further in the misty magic; they gain a failure.
Countermagic or Follow the Flow: A character trained in Arcana may attempt to sense the presence and direction of flow of the magical energy that cloak the island (DC 19); doing this earns one success for the party, while failing earns the party a failure. Once the presence of the magic has been sensed, a trained character may attempt to countermand the cloaking spells here in order to eliminate them, but doing so is very difficult (DC 29). A character that makes this check earns two successes, while failing it gains only a single failure. A character that uses dispel magic against the fog earns an automatic success for the party.
True Navigation: The characters may attempt to simply use their Perception (DC 23) or knowledge of Nature (DC 19) to navigate. Using such a skill earns either a success or failure for the party. Alternatively, a character could make a History check (DC 19) to remember details on the locations of the lake's islands; the party can earn only one success this way (although they could conceivably earn multiple failures!).
Watch the Ghouls: During and after the attack of the sodden ghouls (see Complications), a pc could try to discern the direction of the island by watching their behavior using either Insight (DC 19) or Religion (DC 19). A daring character might also swim in pursuit, using Athletics (DC 20). The characters earn successes or failures for any of these instances.
Rituals: Using a divination or weather control ritual earns the pcs one to three successes, depending on the ritual, its level and how cleverly the party uses it.
Complications: As the pcs get closer to the island, they enter a more active layer of the island's defenses. After their 5th success, the party is ambushed by a trio of sodden ghoul wailers (OG 154; level 9 soldiers), who attack from the water, attempting to pull the boat's pilot into the water before dealing with the pcs themselves. The round after they attack, two more sodden ghoul wailers grab the boat from under the water and attempt to tow the vessel away. Each round until that the ghouls tow the boat, the pcs lose one success.
As soon as the pcs defeat the three sodden ghoul wailers above the water, the other two retreat into the depths unless any pcs are in the water, in which case they attempt to drag them under and slay them. If the pcs want to attack the two ghouls under the water, they must enter the water or hole the deck of the boat.
Each time the pcs achieve a 5th success, they are attacked by another group of ghouls unless they are still dealing with the first group. In practice, this means that they must continue to work on the skill challenge while fighting the ghouls, or they will end up fighting group after group of them without ever making headway.
Success: When the pcs achieve their 8th success, read the following:
In the mist ahead, a rocky island starts to resolve itself. A short pier, inexpertly constructed of wood, bobs above the waves, with three small rowing craft attached. You can see the suggestion of a steep upward slope, but the thick vapor in the air makes it impossible to tell more.
Failure: The pcs become hopelessly lost. It is full dark by the time they finally find shore, and it takes until almost 2 a.m. to return to the Delphinate. The pilot who took the pcs on this journey, if still alive, must be impressively compensated or he swears off the party thereafter.[/sblock]
Now, after an initial failed attempt- rarely have the dice counted so heavily against these players!- the pcs discussed using a ritual (can't recall the name) to function underwater and tie themselves to the bottom of the boat. They also did extensive records searches, cartographic analysis, etc. They bought a compass (which I decided will let them remove a failure). They've taken a bunch of actions not in my "likely to try this" list, and I've gone with those actions (although some are futile).
Skill challenges are no more a straight jacket on an encounter than the fact that a monster has AC and Hit Points means the only way to deal with it is to kill it.