Flags!
Balls!
Masks!
Poles! Fluid rules! A sample:
Calvin:
I touched you with the ball. I move to third base.Hobbes:
Not until you sing the tiger song.C:
But I was in the no-song zone.H:
But I have the flag, which makes the no-song zone a song zone.C:
Fleabag!H:
Chowderhead!(Fight ensues).
Finish with
The I'm Very Sorry Song.