This year, I was curious how they'd handle 12/21/12, the date at which the "long count" comes to an end. Some folks have made a lot of fuss about this (cf. Y-2k*), as if time itself ends when we reach the end of a measurement of time. I've assumed that, just as a car doesn't suddenly fall to pieces when its odometer reaches 999,999.9 miles, but just turns over and starts again at 000,000.1, so too wd the Mayan calendar.
Turns out I'll have to wait till next year to find out. Opening up the new calendar, and admiring the art therein and the explanation in the front about how the various interlocking Mayan calendar systems work, I discovered when I reached the last page that their calendar for December is unfinished, ending at December 21st (day 184.108.40.206.0 in the long count). After this follows a note about how to order their 2013 calendar ("20% off; . . . offer expires December 21, 2012"--I thought this last touch was a hoot). As an added bonus, the art for that page is the Tortuguero Monument 6 ("the only text in the Maya world known to mention December 21, 2012 AD.").
So, I guess we'll have to wait and see how they handle the start of the New Count. It's rare for a civilization to have a mechanism for marking the End of an Age (as Tolkien wd have called it). The Mayans clearly thought a system that cd cover every date between August 11th 3114 BC and Friday December 21st 2012 was good enough for government work. I tend to agree.
*or, at a slightly less significant but similarly fussy point, folks who insisted the new century and millennium started at 2001 rather than 2000. Or, to harken back a few decades, the dawning of 'The Age of Aquarius'. At least we got a good song out of that one.