This is a game/exercise that you create on the spot. It’s basically a choreography. The group leader picks a movement that he likes and calls it “1.” The next person adds a move and calls it “2.” Everyone rehearses 1+2. Now the next person adds another move and calls it “3.” Everyone rehearses 1+2+3. And so on, linking the sequence together into a smooth, flowing movement.
For fitness, you’ll want to mix things up with a diversity of moves. Some flowing, some focused, some fast, some slow. If someone chooses an upper body movement, try to follow with a lower body step, squat or lunge. If someone does a powerful jump, follow with a slow, graceful sliding movement or a couple of quick hops. The point is to make the sequence both holistic and integrative.
In any case, keep adding movements and rehearsing the sequence each time. Eventually, your memory capacity will be taxed and you’ll want to either call for a stop, or better yet, a cyclic return to the original movement. This way, you can loop the whole process and turn the phrase into a musical-movement theme.
Clearly, this process requires a certain amount of leadership, but also a willingness by the leader to get out of the way. Guide the rehearsal, but don’t interfere if someone chooses movements that aren’t to your liking. The point is to work with what you’ve got. If someone makes a poor choice, just keep working to smooth out the sequence.
Ultimately, the whole thing tends to work itself out. Everyone in the group gets to have a voice and everyone gets to work through the rough spots. Once you get a sequence dialed, you might want to write it down for future use, or just let it go and create a new one next time around.