This is a quick exercise that stresses quick reaction and commitment. It is very simple and works well as a closing game for a class or a workshop. It is more appropriate for larger casts, 6-12 people, or possibly more.
The game consists of a series of quick scenes (usually 15-60 seconds), with edits called by the coach (using the command "Bounce!"). Whenever a bounce is called, every in the cast (whether they were in the previous scene or not) must decide whether to be in the next scene or not, and then instantly commit to their choice. The next scene starts right away.
This may result either in everyone in the cast being in a scene, or no one. The former is a good opportunity for the players to practice being a background character. The latter is a good exercise in patience.
When there is either no one in a scene, or just one person, it may be tempting for the coach to immediately call bounce. It is recommended that these moment be allowed to go on for a bit. It is important for players to be used to being on a stage alone. An empty stage and dead air are also deeply uncomfortable to most performers, so this opportunity can calm their nerves about it in the future.
The coach must be very strict about the instant commitment rule. Whenever someone waffles, they must be called out. Players are either in or out of the next scene.
There is any number of variations on this exercise. This particular version was developed at Comedy Corner, at the University of Florida.