"The cataclysmic extinction level event that the Mayans prophesized began its Armageddon on December 21, 2012, and although this projected date seems correct, one must account for the corrections made to the Gregorian calendar which would result in a missing day of every century which rounded up was 365 days, 5 hours, 48 minutes, 45.25 seconds to 3651/4 in the Julian calendar that was used before the Gregorian, which shifted the disappearance of a period of 14 days! Pope Gregory, authorized the conversion to the Julian in 1582, which shifted the calendar by 11 days, ending the calendar leap from March 4, 1582 to March 15, the next day. In actuality the new calendar year was losing 30 seconds from the solar cycle annually, and add this to the fact that the Julian Calendar, adopted by Julius Caesar in the 8th Century made a leap of 67 days to sync with the solar cycle, and upon his death, there was confusions with the methodology involved, with the changes of leap year ever 3 instead of every 4 years. So recalculating the Great Cycle in its entirety against the modern calendar, taking into account the faults and adjustments, the prophesized date would be….October 28, 2011."
[link to thewatchers.adorraeli.com]

(Note: the Mayans did not say that there is an extinction level event. What they did say is that there will be an end to one cycle and the beginning of a new)

this is especially notable for those of you who follow Patrick Geryls work
He seems to be correct on quite a few things
time will tell