In a mental institution a nurse walks into a room and sees a patient acting like hes driving a car. The nurse asks him, Charlie, what are you doing?

Charlie replied, Driving to Chicago! The nurse wishes him a good trip and leaves the room.

The next day the nurse enters Charlies room just as he stops driving his imaginary car and asks, Well Charlie, how are you doing?

Charlie says, I just got into Chicago.

Great, replied the nurse. The nurse leaves Charlies room and goes across the hall into Bobs room, and finds Bob sitting on his bed furiously masturbating. Shocked, she asks,

Bob, what are you doing?!

Bob says, Im screwing Charlies wife while hes in Chicago!