Obviously I went to a meaner elementary school than most. My coworkers had never heard the following joke/insult:

Kid A: Want to lose ten pound of ugly fat instantly?
Kid B: Sure.
Kid A: Cut off your head.

Or...

Kid A: Do you have HBO?
Kid B: Yep.
Kid A: You have horrible body odor?!?!?

I could go on for hours with these school yard shenanigans.