The Mayans didn't really predict anything apocalyptic with their calendar. Their devised system of measuring time simply stopped at the year 2012 and couldn't progress.
I know, Fendante. I just like to laugh at all the silly people who love to make end of the world predictions. There seems to be big one every year, it's ridiculous. And on a completely unrelated note: don't laugh, Darkwings. That could happen. I've already got my 'in case of zombie apocalypse' bunker ready. ;p