My fave bumpersticker EVER!!!: "My kid beat up your honor roll student"
My favorite bumper sticker is one I first saw 11 years ago in the Smashing Pumpkins (one of my all time fav. bands) music video for 1979 is "Proud Parents of a D Student." I'd like to put that on my car.
I also agree that "Will teach for crayons" is good and kid friendly.