7734
My favorite little hidden gag of the film is the number 7734 written on the bus Pecker rides at the start of the film. I would've never noticed it, but John Waters points it out in the DVD commentary. "7734", of course, reads "hELL" when viewed upside down. It's childish, to be sure, but I love the fact that he stuck it in there.
A lot of strange things happen in this world. Things you don't know about in Grand Rapids.