A game where when someone says something stupid and you get to hit them on the head for it. After someone says the stupid statement, you immediately say "That's sum." while rubbing your fingers in the air like the sign for paying money.
Mick, "I drank 7 out of the last 5 days"
Al & Calvin, "That's sum, asshole (rubbing fingers in the air)."
then Al & Calvin each get to slap mick on the top of the head.