Tales of Viridia
Some encounters (primarily non-combat in nature) will be run as Skill Challenges, based on the 4th edition mechanic with the modifications made by Rodrigo on the Critical Hit podcast, plus a couple of my own. These work as follows.
The DM describes the situation and environment, establishes the party’s Goal, and sets up a track of “Passes”, and defines the Lose Condition(s). The players must pass a number of Ability Checks equal to the number of Passes on the track before the Lose Condition happens in order to succeed at the Skill Challenge. All players roll Initiative and act in Initiative order.
When each player’s turn comes around, they pick an Ability or Skill they think will help them achieve their Goal and take the check on it. The DC of the check is determined from a base level DC of the challenge (which the players will not know), and may adjusted by the difficulty of the task being attempted by the Ability Check and how well the player describes the character’s actions. Passing the check crosses off one of the Passes on the track and brings them a step closer to their Goal.
When the player chooses the Ability or Skill, they must explain to the DM how this will help them. They can’t just pick whatever has the biggest bonus, it has to be useful in the current situation. For example, you probably won’t have much use for Wisdom(Animal Handling) if the challenge is to keep a ship afloat in a heavy storm.
A player cannot use the same Ability/Skill combination two turns in a row, nor can they use the same Ability/Skill combination as the player immediately before them. This applies to specific combinations only. For example, if player A used Intelligence(Arcana), they would still be allowed to use a straight Intelligence check next turn. Player B (who acts immediately after A) cannot use Intelligence(Arcana) this turn, but they can still use any other Intelligence Skill/Ability combination.
A player may choose to Help another player instead of taking a check on their own. If they do so, they do not take a check, so do not contribute either a pass or a fail. Instead, the player they choose to Help gains Advantage on their next Ability check.
There are two Lose Conditions, and depending on the nature of the challenge either or both can apply. The first is time based. If the players cannot pass enough checks in a given number of turns, they fail the challenge. An example of this might be a pursuit – they only have so long before their quarry loses them or reaches a safe haven. The second is number of failures. If the party fails a certain number of checks before they can achieve the required successes, they fail the challenge. An example of that might be infiltrating an enemy camp, where too many blunders will alert the sentries to their presence.