On long flight, a woman is sitting next to a lawyer. She wants to sleep, but the lawyer does not stop talking.
"Let's play a game" - he suggests.
The woman ignores him.
"To make it interesting" - he continues - "if I answer incorrectly to your question, I'll pay you $50. If you answer incorrectly to my question, you pay me $5."
The woman agrees, and the lawyer asks the first question.
"What is the distance between Earth and the Moon?"
The woman hands him $5. Now it's her turn.
"What goes up a hill with three legs and comes down with four?"
The lawyer is astonished. He frantically surfs the Internet, searches his pocket encyclopedia and asks his scientist friends. He finds nothing. Hours later, when finally giving up looking for the answer, he wakes the woman, hands her $50 and asks:
"So, what is the answer?"
Without saying a word, she hands him $5 and goes back to sleep.