I think it's Mayan Scholars Carl Calleman and John Major-Jenkins who disagree on the Mayan calendar reset date of either October 28th 2011 or December 21st 2012 respectively.
They're both cool guys and place a lot more emphasis on the meaning of these cycles than the actual tick over date from interviews I've listened to. The video above explains the kind of events that are anticipated. I'm quite partial to George Kavassilas' date of the equinox 2013 not solstice 2012 but don't let that interfere with bookmarking the video.
