Have the group count from one to ten. The larger the group, the harder this is and the longer it can take. Start by giving them instructions and letting them ask questions, but don't allow them to plan any strategy (e.g. there should be no designated order). The rules:
- Only one person can talk at a time; if two people speak at once, the group must start over.
- No one person can say two consecutive numbers.
- No gestures allowed
If they become good at it, have them try with their eyes closed.