Sheldon: Where's Howard?
Raj: He took the day off.
Sheldon: Oh, let's take advantage of his absence and tell the kinds of jokes only physicists get. I'll go first.
Okay, here. Uh, Heisenberg is pulled over by a police officer. And the policeman says, "Did you know you were going 85 miles per hour?" And Heisenberg says, "Darn it, now I don't know where I am."