Found posted in a humor newsgroup (rec.humor.funny)
There were once two people travelling on a train, a scientist and a
poet, who were riding in the same compartment. They had never met
before, so naturally, there wasn't much conversation between the two.
The poet was minding his own business, looking out the window at the
beauty of the passing terrain. The scientist was very uptight, trying
to think of things he didn't know so he could try to figure them out.
Finally, the scientist was so bored, that he said to the poet, "Hey, do
you want to play a game?" The poet, being content with what he was
doing, ignored him and continued looking out the window, humming
quietly to himself. This infuriated the scientist, who irritably asked
again, "Hey, you, do you want to play a game? I'll ask you a question,
and if you get it wrong, you give me $5. Then, YOU ask ME a question,
and if I can't answer it, I'll give YOU $5." The poet thought about
this for a moment, but he decided against it, seeing that the scientist
was obviously a very bright man. He politely turned down the
scientist's offer. The scientist, who, by this time was going mad,
tried a final time. "Look, I'll ask you a question, and if you can't
answer it, you give me $5. Then you ask ME a question, and if I can't
answer it, I'll give you $50!" Now, the poet was not that smart
academically, but he wasn't totally stupid. He readily accepted the
offer. "Okay," the scientist said, "what is the EXACT distance between
the Earth and the Moon?" The poet, obviously not knowing the answer,
didn't stop to think about the scientist's question. He took a $5 bill
out of his pocket and handed it to the scientist. The scientist happily
accepted the bill and promptly said, "Okay, now it's your turn." The
poet thought about this for a few minutes, then asked, "Alright, what
goes up a mountain on three legs, but comes down on four?" The bright
glow quickly vanished from the scientist's face. He thought about this
for a long time, taking out his notepad and making numerous
calculations. He finally gave up on his notepad and took out his
laptop, using his Multimedia Encyclopedia. After about an hour of this,
the poet quietly watching the mountains of Colorado go by the whole
time, the scientist FINALLY gave up. He reluctantly handed the poet a
$50 bill. The poet accepted it graciously, turning back to the window.
"Wait!" the scientist shouted. "You can't do this to me! What's the
answer??" The poet looked at the scientist and calmly put a $5 bill
into his hand.