Heh, if anyone ever bets you money that the world will end on x date, you should take it. Either you'll win the bet, and collect the money, or you'll lose the bet, and it won't matter because the world will have ended. It's win-win . . . well, sorta.
By the way, though, I heard somewhere that they discovered some new evidence that the Mayan calendar actually doesn't end in 2012. Apparently, at least according to what I've heard, the new evidence they've found says that it goes for at least another 7,000 years.
. . . Phew.