Einstein gets on a plane. He knows it's a long flight, so he turns to the man next to him and says, "Its a long flight, why dont we play a game? I'll ask you a question, and if you cant answer it, you give me $5. Then you ask me a question, and if I cant answer it, I give you $100." The man agrees, so Einstein goes first and asks his question. "What is the exact distance from the Earth to the moon?" The man thinks and thinks, but he cant find the answer. He says, "I dont know," reaches into his pocket and gives Einstien $5. Now it's the mans turn, so he says, "What goes up a hill with 2 legs, but down a hill with 3?" Einstein thinks and thinks and thinks, but even with his great mind and extensive knowledge, he cant think of an answer. So he reaches into his pocket, and gives the man $100. He is greatly confused, though, so he asks the man, "Before I take my next turn, what does go up a hill with 2 legs but down a hill with 3?" Without skipping a beat, the man reaches into his pocket and gives Einstein $5.