3-6 players. Player One sits or stands by herself in the middle of the floor; the other players on the sidelines. She begins improvising a piece. After the mood/style seems established, any other player may go to the middle and join her in the piece. At various intervals, other players also do this until all have joined the group (note: being in the middle does not mean you have to play all the time – you can and should have pauses where you listen). As soon as all are out there, one player (any player) leaves the group. Other players leave at intervals until only one player (any player except the starting player) remains, who brings the piece to a fitting conclusion. Repeat the game with a different player starting the game each time.
Variation 1: Set the ‘join’ or ‘depart’ interval to ten or fifteen seconds and make it a very rapid game, and when it is down to one, start over adding players again. Let the game progress through a number of cycles; perhaps setting maximum number of cycles or a time limit.
Variation 2: In concert, invite the audience to join (no more than one at a time) the game; have a table with small percussion instruments available (they may also use their voice or body percussion). You can make it open to all, or have a show of hands before the game starts who would like to join the game, and limit it to a certain number (not exceeding the number of ‘regular’ players).