As for the Mayans, maybe they just ran out of space or got tired or writing? Simply enough, you can't expect them to make a calendar that goes on forever, they had to stop somewhere and so it happens to be 2012... a random, meaningless date.
I agree too.
Storm, a slight reference is one's religion is not forbidden I presume. Just delete the troll's posts, and that's all.
So let me express my views on the subject.
The world is not going to end in 2012, simply because you cant rely on an extinct civilization's calendar, who I admit, they were maybe, the greatest civilization and culture on the humankind history. But you cant say that simply because they didn't make a calendar that lasts forever, that the world will last as long as the calendar 
Thats ridiculous!
Lets just say, that I am an engineer, and I decide to build my own custom car. I use the best materials and alloys, and a Dodge Viper's engine. But unfortunately, I only have a speedometer of a Ford Mustang, and goes up until only 110 miles per hour.
"Bummer! oh well, I will use that, i got no other choice". So my car can go as fast as 200 miles per hour, but the meter can only show up to 110 mph. Does that mean that it cant reach a speed faster than 110 mph?
Oh course not.
There, I just proved that Maya's calendar doesn't define when the world ends. Unless people suggest that it is a magical calendar, that shows the future 
But that's not the only reason, I reject the 2012 doomsday.
I am a skepticist myself, meaning that every "open-minded" theory I don't believe, until there is proof of it.
UFOs = non-existent for me (I have many reasons for this)
Ghosts = nonexistent
etc
What I think is this:
It is fact, that many international companies, like big shot Banks, and computer companies, possess a lot of the world's wealth. Now, every doomsday theory, that goes international wide spread known, is pretty good for all the rich in the world, including these companies. Why, you may ask?
Because when people truly believe that the world is going to end soon, they are living their lives as best as they can, meaning = spending money. Those with power (politicians and such), those with wealth (company owners), and the "strong" people of the world, want nothing more, than people spending their money.
The global wealth is like an old scales 
, when the poor lose money, it all goes UP, not down. And so the 1 side gets heavier and heavier with wealth, and that is why there is a global financial "crisis".
Its all a big, very well thought propaganda. I know, that you will say I am imagining schemes and plots, but these are my beliefs on the subject, and I am sure that some people in the world agree with me. All that someone needs to do, is start out a rumor, then "invent" some sort of "proof", like the Maya calendar, and then the rumor can turn into a big theory, that many people WILL believe, and every time this happens, some people WILL believe it, because there is something in all of us, that makes us create something fictional and exciting, scary but big and unique, like the end of the world for example.
All these movies that each show a soon-to-come end of the world? Some people thought of a story, the story turns into a movie, and the movie proves that human imagination can not be only wild (just think of the Greek Olympian Gods, very interesting and exciting Mythology), but also realistic and terrifying, like the end of the world, which is inevitable, but nobody can predict when it will come.
The earth is but a small little piece of a galaxy, and our galaxy is but a very small piece of the universe. We can be hit by a meteorite at any minute, yet this is so difficult and extremely rare to happen, that is like trying to hit a hair with a 9mm gun from 10 miles away. A lunatec may decide he wants the world to end, and somehow launch missiles to US and Russia, causing the typical, "Nobody knows where its coming from" theory, so the 2 most powerful nations in the world bomb each other with nukes, ending the world for good. The USA alone, has enough power to destroy the world many times over.
Yet all these events are so random and improbable to happen, that you can never know when the end of the world will come, unless scientists manage to catch a good look at an incoming meteorite, or the ecologists accurately predict when the global warmth destroys the ecosystem, and eventually end life. But still, these predictions, vary by years or even Decades.
Just think that the nearest galaxy is 2.5 million light years away!!! And we can see as far as a few hundred years away. So even if scientists can predict when a meteorite will hit the earth (if this happened), it would be an estimate of X-Z years.
Besides my religion (christian orthodox) does not consider the Maya calendar as a valid one. That may be irrelevant of course, because we cant take religious things like that by letter, meaning that there may be many people in my religion, who might believe the 2012 theory. But I am just saying this as a reference.
That said, if somewhere in the Bible was mentioned that the world WILL end indeed in 2012, I would still not believe it because...of all the reasons I mentioned above. Nothing is absolute for me, I think I need both religion AND science. Some people want 1, for example being 100% religious, while others might not believe in anything and take science for granted, disregarding every religion there is. I am somewhere stuck in the middle, not too religious, but not the opposite either.
These are my thoughts on almost everything that has to do with doomsday theories, including the 2012 one.
Thanks for reading, I hope you are not asleep by now!!! 
(He mentioned Christianity, he mentioned religion. OMG!!!! 
) (Trolls, are you ready? OK. Ready, Set, GO!)
