The Maya had not one, not two, but three calendars. These are based on a mathmatical system using multiples of 20, distinguishign them from other Mesoamericans who created calendars. The calendars synchronized time, the solar year and the movements of the planets.

The first of these, The Long Count, moved backwards in time, recording events. Archaeologists have discovered that the date the days that had passed since the time it occurred were based on, Aug. 13, 3113 B.C., pre-dates the Mayan civilization. No one knows for certain why they chose this day to begin their calculation of time; but it's certainly interesting to think about.

And now, a lot of math I don't understand, from "Atlantis Rising" (Karen Garcia):

"The numeration of the Long Count calendar begins with kin for ones, uinal for twenties; one Tun for 18 uinal periods or what we would call months plus a vayeb of five unnamed days; one katun for 20 Tun or 7,200 days which is 19 years, 73 days; one baktun for 20 katun or 144,000 days or 394 years, 52 days and so forth until the multiples reached alau-tun which equals 23,040,000,000 days or 63,080,082 years!

"The Maya spoke of eras of 5,125.40 years each equaling 13 baktuns of 144,000 days each. Each cycle of 13 baktuns was reckoned as an Age or Great Cycle, a specific historical epoch. Like the days and the uinal months, each era had a qualifying meaning represented by its particular glyph. Each Great Cycle was said to be governed by a different Sun with a specific destiny for the evolutions of those incarnating during that era."

The Maya also used 2 cyclical calendars. The solar calendar, Haab, and a sacred calendar, Tzolkin. Haab was used for every day events and agricluture, and numbered 365.242129 days more accurate than the Gregorian calendar we use, 365.242500 days). Haab began when the sun was its' peak, July16..

There were 18 months, each with 20 days and named after a diety appropriate to the sesions, and the festivals of each were held during this time. Festivals related to the type of work done during each season and the nature of the time of year itself .

The 5 remaining days were deemed unlucky. During this time, (the 'unnamed days'), the Maya took the week (or most of it) off. Nothing at all was done during this time. Arguments that occurred were believed to end up lasting throughout the coming year. Those born during this time were beleived doomed to misery.

Each day, (grouped in units of 13), had omens associated with it and these were used for astrological divination. Here's a little more math from "Altlantis Rising",

"Twenty-eight of these 13-day weeks equals 364 days leaving an extra day at the end. When 13 years had elapsed, the number of these extra days would equal 13, called kin katun, the katun of the days. The Spanish chroniclers called these kin katuns indictions. When four indictions have passed, in other words, 52 years, the year would begin with a year bearer of the same name. This cycle of 52 years was reached by the Aztecs and other peoples of Mesoamerica in the same manner. Five cycles of 52 years is 260 years, a Great Cycle, also reached by 13 x 20 and called Ahau Katun. Ahau is the word for chief, king, ruler. The Ahau was the key to the nature of the cycle.

"The Tzolkin consisted of a smaller wheel of 13 glyphs rotated with a larger wheel of 20 days, resulting in the 260-day sacred year. Any given day represented a particular intermeshing of the HAAB Solar Year and the ritualistic Tzolkin resulting in a specific forecast.

"The two cyclical calendars, the Haab and the Tzolkin intercalibrated together created the Sacred Round of 52 years called the binding of the years. For only once in 52 years or 18,980 days could the combination of 13, 20 and 365 repeat itself."

This calendar and its' cycle was both central and sacred to all Mesoamerican civilizations. They interpreted past, future and present with it. It seems a sort of time wheel, as though the combining of all three could create a sort of window through all of it.

The Maya perceived themselves as part of the mind of the Sun, to them the mind and center of the galaxy. Suddenly, around A.D. 843, at the apparant peak of their civilization, the ydissappeared. The Yucatan jungle grew over their pyramids and cities.

Where's they go? Why the obsession with time? No one's really sure.

We are currently in the Maya Great Age, the fifth, believed to be a unification of the four that have preceeded it. It is symbolized by a glyph that means 'shift'. The age is believed by Mesoamericans to have started with Quetzalcoatl in 3,113 B.C and is predicted by many to end on Dec. 21, 2012.

A few oddities, again from "Aquarius Rising":

"In the Mayan Chronology, the date 3113 B.C. date is written 13.0.0.0.0. On Dec. 21, 2012, the date will again be written 13.0.0.0.0. The coefficient 13 in the date 13.0.0.0.0. refers to the completion of a cycle of 13 baktuns. Between the first cycle and the ending cycle, 13 Baktun cycles of slightly less than 400 years each have passed. Therefore, the first Baktun of the new cycle is Baktun zero again."

So a New Year, and a new era coming? Hmmm....