I've already double checked with my boss - I don't get apocalypse pay for working the 21st, so there goes that idea.
As I don't believe in afterlifes or anything like that, and since the world ending it probably going to mess up the whole reincarnation bit even if I did believe in it, I'm just going to figure that if the world ends... well, nobody's going to know, are they? We'll just cease to exist or something. Maybe a bit of pain beforehand and then nothing. Yay? What could we do about it, even if it is to end? Better to not dread those things we cannot change, as it'll only cheapen the rest of the time.
I do not, however, think that the world is going to end and have heard a dozen different and better explanations for the Mayan calendar anyway. But even then, how all-knowing can they be? They're dead. If they were so omniscient, then they probably would have done something about their own doom first.