Guy gets on a bus in NYC. One seat is left. It's right next to a fellow who has a paper bag over his head.

The guy looks at the paper bag; and, being NYC, he sits down.

After a bit, the guy looks over again at the paper bagged head.

The fellow in the paper bag says, "Why are you starring at me?"

The guy replies, "Because you have a paper bag over your head! Why are wearing that?"

The fellow replies, "It keeps the dinosaurs away."

The guy can't help himself and says, "Why do you think that works, are you crazy?"

The fellow replies, "Have you ever seen a dinosaur in New York?"