We do a circle...punch, kick and grab. Someone at random attacks the person in the center with one of those attacks at random. However, there will be one punch, one kick and one grab -- so on the third attack, at least the defender knows which category it'll be.
When I was coming up, we once had a police officer as a fairly new student. He was in the middle of the circle and when the first guy moved to attack, the officer was trying to draw his side arm. Funny thing was, he was in a gi and didn't have a gun.