You Are Fish, What Do You Do?

From Publisher Description:
You Are Fish, What Do You Do? (YAF,WDYD? For short) is a collaborative storytelling game. Unlike more traditional role-playing games, You Are Fish, What Do You Do? does not provide players with a predefined story or a goal, the goal of the game is to create the story. Each player has a hand in creating the world around them and the story as it unfolds, meanwhile the editor takes the player’s ideas and tries to hold them together into a somewhat cohesive story.

YAF,WDYD? is specifically designed to be easy to learn and easily accessible for even first-time players and game-masters.