A person commands, the others follow. The person can command anything. But the command is to be executed only if "Simon says " is said by the head prior to the command . For example: Says the head "sit down", nobody should move, and who only indicates a motion is out. Only if the head says "Simon says: sit down!", to sit down is the right choice - all who do not sit down are out. The person that remains in the end becomes the new commander in a following round.

Simon says!