And now, the third game! I probably won't actually stop the games here, because I like the level of activity they bring to the board, not to mention I'm getting other ideas.
Anyway, welcome to the Alternate Universe Game. In this game, you start by posting a short summary of a story and its characters, and then someone else will reply to that with an idea for an alternate universe for them. These suggestions can be anything, whether it's a setting change, a change in a key plot point, or anything else you can think of. You then respond to that by writing either a scene in this new universe, a summary of what would change, or any other form you can think of, provided that you provide a clear idea of what's changed. Once you have given an alternate universe scenario to another person and they've responded to it, you are welcome to give them a different one.
I don't know if I explained that well at all, so if you're unclear on the rules, feel free to ask me or look at whatever other posts there have been for examples.