Suggestive or nasty bumper stickers.
One of the lunch ladies at our school parked her car in front of the school everyday. The bumper sticker said, "If you don't like my driving, call 1-800-F***You" (written out, not starred).
Every once in a while, a license plate sneaks through, too: Iluvit8 was one I saw.
I think that license plate is "I Levitate". I can't come up with something naughty for it.
There was one near my hometown that said "4nic8" or possibly "fornic8". That was caused quite the hubbub and was yanked by the DMV.
I levitate would have an "e" in it, not a "u".
Of course, but some people can't spell.
Or somebody else already took the "e" version.
In high school a girl I hung out with got her first car. Flirty pink convertable. And Daddy got her a custom lisense plate of her choosing.
She chose ISWALW(I think, its been awhile, but it was something like that. And yeah, it was supposed to mean I swallow. No need to try and figure out if it could've been innocent, she was proud of it and explained it to those who didn't "get" it.)
Her father didn't catch it until a teacher called him and pointed it out.
After that she had a perfectly normal, random type plate. She still had her flirty little car though. She didn't lose that until she got pregnant. (To be fair: She straightened out considerably when her son was born and now gets very embarassed about being reminded how she acted in school. But I still think a parent might want to have a plate explained by their child before agreeing to have a custom plate made for them.)