A cardboard box isn't always empty on the inside. :(
A: You can tune the lawnmower and the owner's neighbors don't mind if you don't return the sax when you borrow it.
Q: What's the difference between zombies? A: Zombies make honey, and zombies don't.
A coconut!
You dye a little on the inside.
Shoot the guy driving the cardboard box.
A homeless epileptic.