Stand in a circle
Someone goes into the middle and introduces a rhythmical sound and movement
Everyone does it and then moves around the room doing it.
On Command "Change!" start doing another different rhythm moving around the space.
On Command "Meet!" partner up with some else and do your rhythms to each other.
On Command "Return!" Come back into the big circle with all your different rhythms and movements.
Without trying make a conscious effort create a unified rhythm and sound.