NASA has already spent some time explaining why all the 2012 End of the World theories are as stupid as those who postulate them. This video is not by NASA, but it summarizes things perfectly.

Of course, the doomsday imbeciles will not care about reality the same way rapture imbeciles didn't care about reason and logic. But hey, if at least one of them realizes their stupidity after watching it, it would be worth it. [Thanks Karl!]