Complementary Shapes

One person turns to the person next to them & makes a sound & motion,
person 2 responds with complementary sound & motion. 
play is passed around the circle (2 to 3, etc.)

Coaching notes: depending on the group's readiness, focus can be put on making dynamically opposite choices, thinking about physical levels (e.g. high vs low), quality of movement (e.g. sharp/rigid vs. loose/fluid), vocal quality (e.g. loud vs. quiet, long vs. short), etc.  The first step is getting everyone out of their heads and trusting their gut instinct.  After some time or when this exercise is revisited, focus can be put on dynamics.