Nearly every major religion has a celebration this time of year - Jews have Hanukkah, Buddhists have Sanghamitta, and Christians have Christmas. What we're really all celebrating, though, is that the days will start getting longer soon. Tomorrow, or late tonight depending where you live, is the Winter Solstice. As Infoplease explains:
Sat., Dec. 22, 2007, 1:08 A.M. EST (06:08 UT), marks the solstice—the beginning of winter in the Northern Hemisphere and summer in the Southern Hemisphere
In astronomy, the solstice is either of the two times a year when the Sun is at its greatest distance from the celestial equator, the great circle on the celestial sphere that is on the same plane as the earth's equator. In the Northern Hemisphere, the winter solstice occurs either December 21 or 22, when the sun shines directly over the tropic of Capricorn; the summer solstice occurs either June 21 or 22, when the sun shines directly over the tropic of Cancer. In the Southern Hemisphere, the winter and summer solstices are reversed.
Pagans and other religions celebrated the winter solstice because the days stopped getting shorter:
Astronomical events, which during ancient times allowed for the scheduling of mating, sowing of crops and metering of winter reserves between harvests, show how various cultural mythologies and traditions have arisen. On the night of Winter Solstice, as seen from a northern sky, the three stars in Orion's belt align with the brightest star in the Eastern sky Sirius to show where the Sun will rise in the morning after Winter Solstice. Until this time, the Sun has exhibited since Summer Solstice a decreasing arc across the Southern sky. On Winter Solstice, the Sun ceased to decline in the sky and the length of daylight reaches its minimum for three days. At such a time, the Sun begins its ascent and days grow longer. Thus the interpretation by many cultures of a sun reborn and a return to light. This return to light is again celebrated (at the vernal equinox, when the length of day equals that of night.
The solstice itself may have remained a special moment of the annual cycle of the year since neolithic times. This is attested by physical remains in the layouts of late Neolithic and Bronze Age archaeological sites like Stonehenge in Britain and Brú na Bóinne (New Grange) in Ireland. The primary axes of both of these monuments seem to have been carefully aligned on a sight-line framing the winter solstice sunrise (New Grange)and the winter solstice sunset (Stonehenge). The winter solstice may have been immensely important because communities were not assured to live through the winter, and had to be prepared during the previous nine months. Starvation was common in winter between January to April, also known as the famine months. In temperate climates, the midwinter festival was the last feast celebration, before deep winter began.
Wikipedia: Winter Solstice
The farther north you live, the more you have to celebrate. In the Pacific Northwest, the days are only eight and a half hours long this time of year. There's not much opportunity to walk in the sunshine, even on days when it's not raining.
There are, of course, lots of Christians who seem to think they invented the holiday. That's not quite true:
Christmas or Christ's Mass is one of most popular Christian celebrations as well as one of the most globally recognized midwinter celebrations. Christmas is the celebration of the birth of the God Incarnate or Messiah, Yeshua of Nazareth, later known as Jesus Christ. The birth is observed on December 25th, what was the winter solstice upon establishment of the Julian Calendar in 45 BC. Banned by the Catholic Church in its infancy as a pagan, or non-Abrahamic, practice stemming out of the Sol Invictus celebrations, Christians revitalized its recognition as an authentic Christian festival in various cultures within the past several hundred years, preserving much of the folklore and traditions of local pagan festivals. So today, the old festivals such as Jul, Коледа and Karácsony, are still celebrated in many parts of Europe, but the Christian Nativity is now often representational of the meaning. This is why Yule and Christmas are considered interchangeable in Anglo-Christendom.
Wikipedia: Winter Solstice
The first war on Christmas, in other words, was waged by Christians. Actually, I think it was the only war on Christmas, but some morons disagree.
It's a special day. No matter how you choose to celebrate it, Happy Holidays.