Son: Dad, what is an idiot? Dad: An idiot is a person who tries to explain his ideas in such a strange and long way that another person who is listening to him can't understand him. Do you understand me? Son: No.
A man phones a mental hospital and asks the receptionist if there is anybody in Room 27 She goes and checks, and comes back to the phone, telling him that the room is empty "Good," says the man. "That means I must have really escaped."
