There were 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 buisness, 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 irratibly 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 deciced 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 the  
his hand.