Scientific American: Neither the Maya nor world calnder ends December 21, 2012
I think the biggest takeaway - if we can already accept that the world was unlikely to end on 12/21 - is that the image usually bandied about as "the Mayan Calendar" is of an Aztec artifact made 400 years after the decline and disappearance of the Maya:
(From the article on the Aztec Stone of the Sun)
