If we are discussing goofy crap on cars how about the little stickers every SUV owner is putting in there rear windshield showing the cartoon figure representing themselves? Is this so rescue teams know who to look for in the vehicle? Is it the modern "Baby on Board" sign? Are you competing with the Simpsons?
Most telling personalize license plate I've seen is the hot girl in the hot car with "Waz-Hiz" plates. They should just use "GLD-DIGR"