Vamping on RSA's post... here's a fun math puzzle, from In Code, which has several samples to tickle the noggin...

In a game similar to "let's make a deal", there are three doors. Behind one is a big prize... I don't remember what, but let's just say it's fully modded and hacked x-box360. Or whatever...

The host asks the contestant to choose a door. When she does, he then goes and opens one of the remaining doors with no prize behind it. He then offers her the opportunity to keep her original choice or to change it.

Question:

If the contestant changes her guess does she:
a) increase her odds of finding the prize,
b) decrease her odds
c) make no change in the odds.

I'll post answer and explanation Monday, unless someone gets it before then. If you've read the book and remember the answer, please don't leave spoilers. If you haven't read the book and don't remember the answer from some other source, give it a guess. The answer may surprise you.

If you get it wrong the first time, don't feel bad - so did I...