Ahh... Paradoxical fun!
A barber shaves everyone in town that does not shave themself. Does the barber shave himself?
Another riddle which can be answered:
A man is in a helicopter. It is running low on fuel. It is extremely foggy with only about 20 meters visibility. He is next to a building where someone is working. The pilot writes a sign "Where am I?" The office worker replies "In a helicopter." With that, the helicopter pilot knew how to return to the airfield where he landed safely.
How did he do it?
