The Inspector at the Asylum

The director of a mental asylum is showing an inspector around. They come to a room with a single patient sitting on a bed and laughing.

“Why is he laughing?” asks the inspector.

“Oh, that’s Carl,” says the director. “He tells jokes to himself.”

“Hmmm,” says the inspector. “He just stopped laughing. Why is that?”

And the director says, “That’s because he’s already heard that one.”