Make it Rain
When put together, this sounds like a rainstorm, and is a good way to get a group to settle down.
Have the group sit in a circle
Start with a few people in the circle and ask them to follow you as you do the following actions. Then make your way around the circle. And when you get back to the first group, do the next action on the list: Rub your hands together, snap your fingers, clap your hands, slap your thighs, stomp your feet, slap your thighs, clap your hands, snap your fingers, rub your hands, rest your hands on lap.