I know you people believe stuff more or less at random, but this? This is embarrassing for us as a group. No, as a race. The human race should be collectively embarrassed over this. This would be as bad as reality TV if it didn't have a built-in expiration date stamped on it.
First off, even if you are the sort of person who believes that this symbol, or this one, or this one or this one or even this one, mean something to which you can semi-rationally or emotionally relate, you have to admit that basing a belief that the world is going to end on an ancient piece of semi-functional rock is pretty fucking thin. It's beyond thin. It's Karen Carpenter, it's Kate Moss's hipbones. I mean, I get that a lot of people want to believe in angels and demons and a coming zombie apocalypse, and that they base their "serious" beliefs on...well, on a lot less than this, but choosing to believe that the end of the world is coming because this thing doesn't have December 22nd on it is like assuming the world ends every year on December 31st at midnight because you didn't get a new calendar for Christmas. It is beyond ridiculous, and it is the behavior of people who shouldn't have privileges, knives, children, conversations, licenses or credit.
First off, this thing is not a measuring device that should be given any credence by an advanced civilization. In this case, "advanced civilization" means any civilization who has given up worshipping corn gods, tying your wife's tongue up with barbed wire, and using heads for sport. Our measuring devices have numbers and letters on them, and if you want to argue that this is an arbitrary difference, imagine a tape measure where you had to tell someone the couch was "six snakes long." Or someone's temperature was "three pointy face guys." Extreme silliness.
Then, there's how this great mad stone bastard works. It needs two other massive stone wheels to work properly, I believe, and you only ever see this one. The "long measure" of time as calculated by the Mayans requires this disc inside of the other wheely thing, and no one's really doing that. Regardless, you can set this one in the other one and get to December 21 and no further - which is the point at which the Mayans would have re-set this thing and started counting again, you stupid, stupid people. Just a little reading and you can get right to it. I don't even really understand it and I have a better grasp on this than you do, you end of world moron, you. Additionally, it is perhaps important to realize that the Mayans didn't do leap years, and when you try mooshing that system with the one they were using, the world ended eight months ago, and you dumb motherfuckers didn't even notice.
So. What is this, really? An excuse for people to act stupid again? For people to kiss and fuck and fondle people they're not supposed to because the world's coming to an end? So they can be irresponsible and claim this was the reason? So they can spend too much on Christmas bullshit stuff? Just a "belief of the week," where, once you were done with Planet X or Ron Paul or vampires or group supremacy or religious craziness you could move on to this, believe in it until the 22nd, and then move on to "Well, I'm going to hold onto my canned goods and shotguns because the world has to end sometime."
Not soon enough, cousin. Not by a long shot.