This year marks the last series of repeated day/month/years (as long as you omit the century) until January 1st, 2101. What does it signify? Not a damned thing, but it's neat. We're a mere nine days away from the coming Mayan Apocalypse, and 2012 is rapidly drawing to a close.
The end of the year is often a time of reflection on the preceding twelve months, but days like today make me reflect on time throughout human history, on the entirety of my life, and on the coming century.