This morning, Eddy Webb posted on Google+:
I found this to be a compelling problem, and my brain won't let go of it, so I'm writing down my thoughts on the subject so far.
First off, this is talking about classic musicals in the style of West Side Story or Oklahoma. I'm not talking about dance offs or anything else. I'm using Fate Accelerated as a framework, because if you read my stuff you probably know that I'm a big fan of the system, and I think it's suited nicely to be adapted for this.
All combats happen in the form of song, and no combat is finished until the song is finished. Show tunes are usually 32 bars long divided into four sections of eight bars each. The sections are formatted as AABA where the A sections are the melody and the B section is the bridge. This is pretty typical for most American music as well, not just musicals. There is a lot of variation on this, but for the sake of making our game simple, let's keep it AABA. Each A section is going to have a verse and a chorus.
I'm going to assume that the conflict is between the party of PCs and a group of NPCs that has one leader. The Players will choose one person to be the soloist for this song. That person will do the verses for the second and last A sections and they should be the main person for the combat as far as the story goes. The players should choose someone else for the first verse to do the introduction. The main badguy of the scene and the soloist will do contested rolls in the B section. The rest of the players will help during the chorus section of each A section.
Example: Matt, Joe, Eric, and Jason are all characters in a game. The players have decided that Matt is going to be the Soloist for this song, and Eric is going to do the introduction.
1st Verse - Eric does the introduction
Chorus - Matt, Joe, and Jason
2nd Verse - Matt does this verse
Chorus - Joe, Jason, and Eric
Bridge - Matt and Bad Guy both are involved
3rd Verse - Matt
Chorus - Joe, Jason, and Eric
So now that we have that structure set up, I can go into more details about what happens in each part.
1st Verse - In the introduction phase the player doing the introduction chooses one of their approaches and does a roll choosing one of their approaches. The type of roll that they choose sets the tone for the whole conflict. The rest of the Choruses will use the same type of roll, so they need to pick something that fits the group. The GM has to approve of the approach as it needs to fit the tone of the scene. If the roll is a success the player creates an aspect to the scene as per standard Fate rules.
Chorus - Each chorus will have all the Players where were not involved in the previous Verse roll the approach that was chosen in the 1st Verse. If over half (rounded up) of the players succeed then either add an additional free invoke to an existing aspect that was created during this song, or they will create a new aspect if the appropriate aspect hasn't yet been created.
2nd Verse - This verse is about the Soloist setting up for the battle. The player chooses an approach and the GM approves that it's appropriate based on the content of the verse. If the player succeeds then they create a new scene aspect as per standard Fate rules.
Bridge - This is where the main conflict happens. The Soloist and the Bad Guy each get a roll to try to inflict as much stress on the other as possible. The Soloist may use any existing scene aspects to enhance their roll. Whomever causes the most stress on the other is declared the victor of the conflict.
3rd Verse - This verse describes what happens immediately after the conflict. The aspect that can be created in this Verse is applied to the next scene. The difficulty of the roll should be more difficult if they failed the conflict than if they succeeded. The chorus following this verse can add free invokes only to this aspect.
Of course each time a player rolls in a verse, they should describe what they are singing in that verse. A truly talented player may even write a line or two of the verse, but I wouldn't expect all players to do that.
Okay. With this now written, my brain can let go of this idea and I can get on with my Saturday.