FatePlay

The following text is a direct quotation from the web site above:

Fateplay is an interactive method of storytelling, appliable to roleplaying games, Live-Action roleplaying and forms of improvisational theatre. Fateweaving is drawing out the essence of a story and cutting it down to the minimum necessary actions of each individual character for the story to happen. These necessary actions (written as imperatives) are the fates of a play. Distribute them to the actors, and the play has begun.