I was at the SXSW tech conference over the weekend to be on a panel about 2012 doomsday nonsense. Right after, Helen Popkin of MSNBC interviewed me about this stuff:
[If the video above doesn't load, hit refresh; I've found that happens sometimes and refreshing usually fixes it.]
The panel was fun -- I gave an overview to and quickly debunked a bunch of 2012 claims, while JPL scientists Don Yeomans and Veronica McGregor talked about asteroid impacts, and what NASA is doing to calm unfounded fears about them. Asteroids are indeed a threat, but that danger is routinely exaggerated way beyond reality by lots of folks (YouTube fearmongers, I'm looking at you). There's no real danger of the Earth ending in 2012, Mayan calendar-wise or otherwise -- but the real danger is the overhyped fear of nonsense.
Forewarned is forearmed. Be aware of the reality of the situation, and save yourself a lot of trouble.