One more thing...
Whoever came up with that stupid 'riddle' about the gameshow with the three doors (one is the right door, you don't know which one; you choose one and then the quiz master removes one and allows you to either switch to the other remaining one or stick with your first choice; what are the odds in situation two ? should you switch or not ?) should be shot. I work in an I.T. deparment and I'm fed up with that riddle being revived every other damn month or so. Especially since I ended up making a truth table which logically analysed every possible start situation and second choice and whatnot. And guess what ? It's friggin' 50%. That's right, the whole 66% theory is bogus. Yes, if you view it only from the situation "IF I switch, out of three start situations there's only one situation that I lose: if I start out in front of the correct door", then yes, 66% win chance. But you're looking at the situation the wrong way then, since there is more than three situations here. The removal of one door creates a number of new situations - even if you take into account that if you're in front of a wrong door, there's only one possible door that can be removed (the other wrong one). It's 50% win/lose chance.
And as far as I'm concerned, that's that. I don't buy the other explanation because it's a short-sighted view at the situation. But when you're surrounded by geeks, this discussion pops up ENDLESSLY, time and time again. Like an active volcano. It annoys the hell out of me.
So if anyone knows who started this nonsense question, let me know. I figure wiping this bastard off the face of the earth is a favour to mankind and would be worth a few years in jail.

René out.