A computer programmer and an engineer were sitting next to each other on an airplane. The programmer leans over to the engineer and asks if he wants to play a fun game. The engineer just wants to sleep, so he politely declines, turns away and tries to sleep.

The programmer persists and explains that it is a really easy game. He says, "I ask a question and if you don't kow the answer, you pay me $5. Then you ask me a question, and if I don't know the answer, I'll pay you $5." Again, the engineer politley declines and tried to sleep.

The programmer, now somewhat agitated, says, "Okay, if you don't know the answer, you pay me $5, and if I don't know the answer, I pay you $50!"

Now, that got the engineer's attention, so he agrees to the game. The programmer asks the first question. "What's the distance from the earth to the moon?" The engineer doesn't say a word, but reaches for his wallet instead and hands the programmer $5.

Now it is the engineer's turn. He asks the programmer, "What goes up a hill with three legs and comes down on four?" The programmer looks at him with a puzzled expression, takes out his notebook computer, looks through all his references, and after about half an hour, wakes the engineer and hands the engineer $50. The engineer politely takes the $50, turns away and tries to return to sleep.

The programmer, a little miffed, asks, "Well, what's the answer to the question?" Without a word, the engineer reaches into his wallet, hands $5 to the programmer, turns away and returns to sleep.