Skepticlawyer over at Catallaxy (where I sometimes blog) has a nice little summary of the pagan origins of Christmas, before it was co-opted as the pretend birthday of Jesus. Here’s just a snippet:

Romans decorated their doorposts with holly and kissed under the mistletoe. Shops and businesses closed and people greeted one another in the street with shouts of Io Saturnalia! On one day of the twelve, masters waited on their slaves at table while, in the legions, officers served the ranks. A rose was hung from the ceiling in banqueting rooms, and anything said or done sub rosa went no further than the front door. That banqueting could get out of hand is attested to by Seneca, who tells of slaves detailed especially to clean up the spew. The government – in both Rome and the provinces – often laid on free public feasts. In the poem by Statius running through this piece, we’re told how the emperor Domitian held one such feast in the colosseum, somehow combining (and the organisation can only be marvelled at) vast quantities of food with entertainment. The Romans, I should add, had no weekend, no useless and unproductive Saturdays and Sundays, so they looked forward to their sanguinary feriae with considerable relish. The festival of Saturnalia was a time, too, for family dinners, for parties, for amours, for socialising, for wishing others well.

Surely this is something that several of my readers already have extensive knowledge about, but while I’d heard of it, it’s mostly new to me. Also, the Roman city in SecondLife, whose name I can’t at the moment recall, was celebrating Saturnalia last time I was there.

Obligatory Wikipedia entry link. Note that Wikipedia claims the link between Christmas and Saturnalia is tenuous, at least as far as the date goes. The traditions seem pretty clearly related to me.