The base year for the Mayan Long Count starts at "0.0.0.0.0". Each zero
goes from 0-19 and each represent a tally of Mayan days. So, for
example, the first day in the Long Count is denoted as 0.0.0.0.1. On
the 19th day we'll have 0.0.0.0.19, on the 20th day it goes up one
level and we'll have 0.0.0.1.0. This count continues until 0.0.1.0.0
(about one year), 0.1.0.0.0 (about 20 years) and 1.0.0.0.0 (about 400
years). Therefore, if I pick an arbitrary date of 2.10.12.7.1, this
represents the Mayan date of approximately 1012 years, 7 months and 1 day.

Mayan Doomsday Prophecy is purely based on a calendar which we
believe hasn't been designed to calculate dates beyond 2012. Mayan
archaeo-astronomers are even in debate as to whether the Long Count is
designed to be reset to 0.0.0.0.0 after 13.0.0.0.0, or whether the
calendar simply continues to 20.0.0.0.0 (approximately 8000 AD) and
then reset. As Karl Kruszelnicki brilliantly writes:

"…when a calendar comes to the end of a cycle, it
just rolls over into the next cycle. In our Western society, every year
31 December is followed, not by the End of the World, but by 1 January.
So 13.0.0.0.0 in the Mayan calendar will be followed by 0.0.0.0.1 – or
good-ol' 22 December 2012, with only a few shopping days left to
Christmas." – Excerpt from Dr Karl's "Great Moments in Science".

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http://www.universetoday.com/2008/05/19/no-doomsday-in-2012/