No, it's fake. First of all, think about this... The Mayans didn't have computers, so they couldn't type in an algorithm to make a calendar that goes on forever, so they had to stop at some point. Furthermore, their calendar just ENDS there, it's not like there was a post-it note stuck to December 21st, 2012 saying, "DOOMS DAY! EVERYBODY FREAK OUT!" It just stopped there. Maybe they all planned to kill themselves on that day, or maybe they all thought that aliens were coming to take them to their home planet. Furthermore, the need to expect an end is part of the human condition. People are always talking about death, or want to know what time something will end, they drive quicker to get to the END of their trip, to their destination. Some people want to know the end so badly that they skip to the last page of a book first, then read through it. See what I'm saying? I mean remember Y2K? Were's still here aren't we?
To further prove that last point, here's a list I found of TWO HUNDRED TWENTY predicted dates throughout history for the end of the world.
http://www.bible.ca/pre-date-setters.htm