"If the Music's too Loud, You're too Old!"

"186,000 miles per second. It's not just a good idea; It's the LAW."

"My Wife's other car is a Broom"

On a boxy Toyota Scion:
"You've just been passed by a Toaster"

One I'd like to put on my car:
"Do you have to FAIL a driving test to buy a BMW?"