This is it, people: The bona fide, for-real, I-mean-it-this-time Big One.
Today is December 21, 2011: exactly one year until the end of the Mayan Long Count calendar. This calendar starts measuring time at a mythical creation date of August 11, 3114 BC, upon the completion of 13 b'ak'tuns (1 b'ak'tun = 144,000 days, or roughly 394 years). Another 13 b'ak'tuns will be completed on December 21, 2012.
This is the date that has caused so much hysteria amongst the lunatic fringe and on late-night talk radio, such that it is popularly taken to be an end-of-the-world candidate (the premise of the Roland Emmerich explosion-fest 2012). In reality, it's just another example of fin-de-siecle hype of the same kind that plagued us a decade ago when the Western calendar rolled over to 2000. Somewhere out there, gullible people will believe that the Mayans had special insight into the future that other cultures (who managed not to go extinct) do not, or that freaky things happen every time someone's historic calendar resets to 0.
In 1982, a planetary alignment was supposed to trigger the "Jupiter Effect," in which the combined gravitational pull of the rest of the solar system was purportedly going to trigger earthquakes and other catastrophes. Apart from schoolkids running around at recess screaming "Doomsday!!!" nothing happened. In 1988, Edgar Whisenant published a book titled 88 Reasons Why the Rapture Will Be in 1988. When the Rapture failed to arrive on schedule, he followed it up with an updated 89 Reasons a year later, before fading into well-deserved obscurity. On New Year's Day, 2000, the Y2K bug was going to end civilization when all the computers were terminally confused by the two-digit date "00" and turned into bricks. Since the Millennium bug was caused by a known engineering oversight, it was easily prevented, and actual computer errors amounted to a minor inconvenience. Planet X was going to speed past Earth in 2004 and cause all sorts of mayhem. Not only did Planet X fail to appear, but it failed to exist. Harold Camping predicted the end of the world for September 1994, May 21 and October 21, 2011, with predictable results.
As for December 21, 2012, this, too, shall pass unremarkably. In the meantime, however, get ready to be inundated with all the mass panic you can stomach.
I wonder whether the Mayan calendar accounted for leap years? I'd hate for the world to end a day prematurely.