Since the media in general has decided to not give the facts about what is happening with the Mayan calendar in a couple days, I figured I better take care of it for them. I'll start with this: there is no evidence of either a Planet Nibiru or Planet X on a collision course with Earth. These are purely fictional and I will not even mention them again.
Second, there is no prophecy concerning December 21, 2012. December 21 is simply, based on a common interpretation, the end of an "era" on the Mayan long count calendar. This is the date which is the end of the last "bak'tun" (a measure of 144,000 days) which was recorded by the Mayans. This means about the same thing as New Years Day. Which is to say, practically nothing. What's more, the end of this bak'tun may signify even less since bak'tuns are likely not the highest unit of time the Mayans used. Just like a millennium is a large unit of time, but not the largest by far. The idea that this lack of recorded dates in the future could signify the end of time is like saying that because my computer won't show me dates past December 31, 2037 that must be when the world will end.
The fact that so many people have latched onto this hoax and almost nobody is reporting on it responsibly is disturbing. The very concept that any calamity could be linked to a calendar with an arbitrary start date is mind-numbingly simple to discard, and yet so many people believe it could be the case. If you plan to use it for an excuse to have a great party, that's fine. Just don't spend all your money on hookers and blow. You will need it for your January rent.