Did you know of another big influence of Christmas? The big roman holiday in honour of the god Saturn. The Saturnalie-party. It was held every year between the 17,th and the 25,th of december since at least 400 BC. A lot to eat and drink was a given. Some sexual things took place too. These things are nowadays toned down too just the chaste kiss under the mistletoe. When the Romans turned Christian during the 4,th century the christian leaders promised that they could continue to celebrate their party as long as they did to Jesus instead. So was his birthday placed on that (the 25,th) date. Noone really know when he was born since it isn't mentioned in the Gospels so the early churchleaders thought it was a good idea to place the date in an already existing festivity to help christianity along.
Okay, not to be a slave to modern culture, but I heard about the Saturnalian as the analog for Christmas in the
Big Bang Theory, and it's actually one of my favorite episodes.
There's more of Christianity that is "pagan" influenced, such as the rabbits and eggs and the very name of "Easter," but we'll leave all that for the religion thread in "Hot Topics."
But anyway, in the spirit of the thread, I don't have much to contribute except some flotsam and jetsam of the brain which says that Jesus' birth was probably more in the warm and not winter months, at least given that there were shepherds guarding their flocks by night or something, and that "White Christmas" by Irvin Berlin is arguably one of the best-selling songs of all time (Bing Crosby played a big part in that, I have no doubt), and that attendance at the American's KFCs in Japan is a popular part of "Christmas" there.
Eh. Worse things have been done in the name of religion. 
