Bored during a long flight, an eminent scholar leaned over and woke up the sleeping man next to him to ask if he would like to play a game.
"I'll ask you a question," the scholar explained, "and if you don't know the answer, you pay me $5. Then you ask me a question, and if I don't know the answer, I'll pay you $50."
When the man agreed to play, the scholar asked, "What's the distance from the earth to the moon?" Flummoxed, the man handed him $5. "Ha!" said the scholar. "It's 238,857 miles. Now it's your turn."
The man was silent for a few moments. Then he asked, "What goes up a hill with three legs and comes down with four?"
Puzzled, the scholar racked his brains for an hour--but to no avail. Finally he took out his wallet and handed over $50. "Okay, okay, what is the answer?" the scholar asked.
The man said, "I don't know," pulled out a $5 bill, handed it to the scholar, and went back to sleep.