To read more on this CLICK HERE and NASA themselves say. This page answers 20 popular questions about 2012. All answers are quite brief and not that hard to understand.
The following Video also talks about the Mayan Calendar 2012. The video is just 3.25 minutes long.
The following video is not about NASA but GLOBAL WARMING and the claim that the Himalayan Mountains will melt by 2035. A very short but informative video gives another reason not to believe the global warming scaremongers.