2 players. Two players sit in chairs facing each other. The game: construct a piece using hand and arm gestures only. Although this game is without sound, the principles of improvisation are the same: come up with a strong idea, repeat that idea, embellish or ornament it, develop that idea in all the ways that you might develop a melodic idea.
Suggestions: Respond to what your partner is doing – steal (imitate) their ideas, integrate them with your own, be inspired by your partners ideas. Remember to be silent (i.e. motionless) sometimes. Create ostinatos (repeated gestures) as accompaniments to solos. Take a solo – be imaginative!