Other kids' games are all such a bore! They've gotta have rules and they gotta keep score! Calvinball is better by far! It's never the same! It's always bizarre! You don't need a team or a referee! You know that it's great, 'cause it's named after me!
— Calvinball theme song
BackWhen asked how to play, Watterson stated, "It's pretty simple: you make up the rules as you go."