Second, there’s the winter solstice on the 21st, the beginning of winter. It’s the day the sun is at its lowest altitude above the horizon in the northern hemisphere and the day is the shortest of the year. The winter solstice is celebrated by many cultures, not including those who have to go to work in the dark of morning and return home in the dark of evening. But be of good cheer: The days will get longer again!
Finally, of course, both of those holidays are trumped by the ultimate on the 21st, THE END OF THE WORLD! (Or maybe just a transition to a new world of sweetness, light, and endless beer for the FSMers.) At least some of the loonier wingnuts (see here for some descriptions) tell us the world will end, basing their story on a misinterpretation of the Mayan calender. Skeptics notwithstanding, you can watch the end of the world live here.
So, Merry Kitzmas, Happy Solstice, and I’ll see you on the other side of the end of the world (maybe…)!