I hated my geography teacher, so each time xhe was retrieving homework from the class I'd make an origami penis and put it somewhere in a pile of workbooks. Each time xhe stumbled on one when reviewing homework she'd lash out and it was a class wide geg. It got to the point where the principal got involved, after which I stopped for a while, and then made more paper dicks for xer. It's probably not the funniest one I know, but it's the one I remember right now.