I would even add that the Mayan themselves condidered that the current cycle was not the first. They calculted a cosmic moment corresponding to what they thought was the start of the cycle ( 3000 BC something ) and conidered the long cycle would contain 13 baktun of 144000 days.

The whole doomsday theory comes from a few hieroglyphs on a broken stone monument found in Tortugero, that seems to say that a the end of Baktun 13, a monument will be erected to a warlike god called Bolon Yookte.

Little is known on that god, and what has been found make him look very much like the Roman Saturn.

Half of the writing has been lost, so the translation is very partial. Some scholars think that this simply refers to "a new era". And not evry one agrees on the exact date corresponding to baktun 13 ( 2011,2012 or 2014 ?) nor even on the so called baktun 13 being 13.0.0.0 or 13.13.13.13. The latter being another 400 years away...

All I know is that 2012 will have some pretty frightening/amazing parties...