From the web page- Overview: The Mayan calendar is one of the oldest and most accurate calendar systems in human history. Using no more than their knowledge of the Earth, Sun, and stars, the Mayans were able to tabulate days, weeks, months, and years from 3113 BC until December 21, 2012 AD. No one knew why the Mayan calendar ended on that date.. On December 22, 2012, a small asteroid swung in from the outer solar system and clipped the moon. For over a year astronomers had been tracking the asteroid, but due to its small size had not thought it a serious threat. It proved, however, to have a much higher density than expected. Its impact with the moon imparted a distinct 'wobble' to the lunar orbit and ejected megatons of lunar material into Earth orbit. Scientists estimate the moon's orbit will return to normal in a few years. But, its erratic orbit will have catastrophic effects on Earth's biosphere during the first year. By the end of 2013, all life on the six northern continents will be extinct. Welcome to mankind's last year… Two versions of this game are available: A PDF (Print and Play) version and a Vassal version.