The date December 21, 2012 has no actual significance in its numbers, but in a rare astronomical alignment of the sun entering the exact center of the milky way while rising when the ecliptic and galactic equator cross during the winter solstice. This event occurs so rarely (only once every 25,920 years) that the Mayans set their callender by it as the end of an age. But this is not the full story behind 2012.
Nostradamus, a sixteenth century apothocary whom many consider to be a profit, left behind a book of illustrations linked to some of his quatrains indicating that 2012 was near the end time. I say 'near' the end time because the illustrations are only a marker for his traditions. The story goes that he had these pictures created because A. He'd seen that our time communicated better through images than words (T.V., Movies, Video Games) and he thought that we would better understand his predictions if the more important ones were illustrated and B. That after making his predictions of the end time, he realized that he'd have to give a specific moment so that we could prevent it, so, in the pictures, he gave clues to the aforementioned rare astronomical alignment as being the sign to watch out for (An alarm, if you will. I.E. the alignment itself is not the cause of the end of the age, but a warning of it).
Oil production in Saudi Arabia is scheduled to peak in 2012.
2012 is an election year, if a change in power occures, inauguration day in 2013 would be a prime moment for a terrorist attack.
An electromagnetic field cycle (Which is the cycle of strength and weakness in the earth's electromagnetic field) will comlete on December 21 2012 (meaning that the field will be on its weakest on that day before beginning to get stronger again over the next 13,000 years).
Many other things can be traced to that date and year, but I won't lst them because, quite frankly, if nothing happens, nothing happens. If something does happen, there's nothing we can do to stop it. All we can do is be as prepared as we would be for any disaster and keep in mind that its not the end of the world, just of the age, a period of time, a simple date, and nothing more.