You know that game show, Let's Make a Deal, right? You know at the end of the show there's the three doors, and one has a car behind it, and the other two have crap?
Yeah, so, say you're the dude picking the door. You choose the first one. Then Monty Hall reveals door #3 to reveal crap. So, when he asks you if you want to switch to door #2, do you? Do your odds increase if you switch doors?
Discuss.
(I have my own explanation, but I'll wait to see what ya'll say.)