That's the year the Mayan calendar ends, which many people believe signals the end of the world.
Whew! I don't have to worry about losing weight and finding a dress for that one. Thanks, Mayan high priests!
By far, the most amusing website I've found pertaining to the upcoming calamity is this one.
Fortunately, a simple device made from paper clips will save you, as this diagram clearly illustrates:
Beware the Duodecimalist!