They did a thing at the conspiracy site Abovetopsecret where their members voted on the top ten conspiracies. The suppression of 2012 came in at # 7.
$1:
A Significant Global Catastrophe Will Happen In December, 2012
3.55% of all votes
The ancient Mayans possessed a sophisticated culture with a unique perception of the universe and the role of the planets in cosmic events. Scholars studying the Mayans have found startling accuracy within the Mayan Calendar as it tracked days and weeks in comparison with astronomical data and events, and which is more precise than the Julian calendar. But the disconcerting discovery is that this highly accurate and painstakingly prepared calendar of cosmic events has an end date of 2012, beyond which no data exists.
According to a growing number of people researching this particular phenomenon of the calendar agree that "something significant" will happen on the end-date. Opinions range from a simple "cycle back to the beginning and start over," to a cosmic catastrophe that will end all life on earth. And as more information becomes apparent, many now believe that "the government" is fully aware of what will happen and is very carefully suppressing the truth. One tantalizing glimpse of this potential foreknowledge lies in the manner in which the "Y2K Bug" was repaired in many mainframe computers -- the problem was simply pushed forward to, you guessed it, 2012.
http://www.abovetopsecret.com/forum/thread449046/pg1There's links to where their members discuss it in detail there, so you get an inside look at the conspiracy mindset, and all the strange things they believe concerning 2012.