I recently got an idea from a woman I met on a message board. She is called Alicia Castillo Holley and can be found at http://www.wealthing.com/

As a fun and interesting way of introducing non-verbal communication, ask people to look around them, find a partner and communicate with that partner using only one finger. Just let them go for it. They can move around, get closer or remain distant. But all they have is that one finger for communication.

I can see how useful this would be for really large groups. In the debrief it might be interesting to see if that one finger also included one very animated face, or other body movement

Sometimes we speakers and trainers are looking for a simple, quick activity for a big group. I think I just found mine.