Err... So because the Mayan calender ended that day that is when the world is going to end? I think the reason it ended was more like something like this:
Mayan #1: "Hey, are you still working on that calender?"
Mayan #2: "Yes, I'm already at December 21 of 2012."
Mayan #1: "2012? Dude! That's so far in the future, by then we probably don't even exist anymore. Don't you have anything better to do?"
Mayan #2: "But if I stop now and future people find this calender... won't they misinterpret it and think the world is going to end in 2012 or something?"
Mayan #1: "Do you really think future people will be that stupid?"
Mayan #2: "No, of course not. You're right, I'm wasting my time here. Let's go do something fun... like sacrificing people to the Gods."
Mayan #1: "Yay! Sacrifice!"
Mayan #1: "Hey, are you still working on that calender?"
Mayan #2: "Yes, I'm already at December 21 of 2012."
Mayan #1: "2012? Dude! That's so far in the future, by then we probably don't even exist anymore. Don't you have anything better to do?"
Mayan #2: "But if I stop now and future people find this calender... won't they misinterpret it and think the world is going to end in 2012 or something?"
Mayan #1: "Do you really think future people will be that stupid?"
Mayan #2: "No, of course not. You're right, I'm wasting my time here. Let's go do something fun... like sacrificing people to the Gods."
Mayan #1: "Yay! Sacrifice!"