nothing will happen, just like last year, 2003 and y2k. It's just dumb theories that try to make people money.
And not to mention the three times Harold Camping got rick-rolled predicting the end
The Jehovah's Witnesses have predicted it several times within the last 200 years alone
I remember in 1982...all of the planets were to align themselves in a straight line and that would lead to the end of the world with a massive gravitational pull, etc. It didn't happen.
Going back to the 1st century after the death of Jesus, many Christians believed that Jesus would be back within a generation or two of his death. When John wrote the book of Revelation at the end of the 1st century AD, he thought the end was near then.
I think the Mayan calendar has ended a couple of times. If I remember correctly, they restart by offering some sun God a blood sacrifice. Basically, they carve someone's chest and rip out their heart while it's still beating, I don't remember what they do after that. That's basically how they keep resetting the calendar. A VERY small minority of people down in Mexico still follow the Mayan way of religion (they only rip out hearts when they need to reset the calendar, I think. Most of the time, they are just drawing blood. I'm still a bit sketchy on my memory though.), so I'm sure someone will volunteer to be that special sacrifice. Also, I think other calendars (Indian, Chinese, etc.) have also put December 21, 2012 as the end of the world. I don't believe it's true, but it's hardly a coincedence.
No shit sherlock! It is not about if it happens or not. It is about having fun while speculating things and pretending that it could happen. For example we know that Santa Claus doesnt exist but it is fun to think so at christmas.