This movie is based from the Mayan's calendar.
Apparently, the world is going to end on December 21st, 2012. Yes, you read correctly, in some way, shape or form, the Earth (or at least a large portion of humans on the planet) will cease to exist. Stop planning your careers, don't bother buying a house, and be sure to spend the last years of your life doing something you always wanted to do but never had the time.