Christmas: A usurpation of the mid-winter Saturnalia Festival. St. Patrick was big on keeping the frolicking holidays, but bending them to his own purpose. Historical records seem to place the actual birth of Jesus in March or April. Facts don't get in the way of the commercial spending binge. All hail the Almighty (dollar/euro/pound/yen).
The big bruhaha this year in the US was all the stores who decided that Thanksgiving was a great day for their employees to not be with their family in a celebration of thanksgiving. So, they opened their doors and let the crowds rush in. Christians don't have to worry about atheists having some pretend war on Christmas. Christians are their own worst enemies. Ask the Pope.
Saturnalia: The Romans liked mid-winter to celebrate something, so Saturn got the festival. This one was usurped for the Christmas myth. Don't get all twisted. Christmas is not a celebration for Jesus. It's a way to get the Pagans to sign up.
Besides Saturn, other pagan dieties are celebrated for much the same reason. Mithra, Horus, Zeus, even Hercules. Christians didn't steal the celebration until 400 AD. Historical accounts have Christ born in the spring, but that would have interfered with the theft of Oestra, the spring festival of fertility.
Pancha Ganapati: The Hindu solstice celebration lasts five days (the Hindus really know how to party) beginning on December 21st. The celebration is in honor of the elephant god Ganesha, who is the patron of arts and guardian of culture. Each day is celebrated by a different color which have special meanings for Ganesha. Golden Yellow creates a vibration of love and harmony within the family, Royal Blue for love and harmony between neighbors and friends, Ruby Red for harmony with business associates, Emerald Green celebrates art and culture, and the last day (which happens to be December 25th) is Brilliant Orange for love and harmony for all. The holiday is celebrated with lights and tinsel, but with a nice picture of Lord Ganesh rather than a tree.
Hanakkuh: This year, the beginning of Hanakkuh December 12th What a perfect time for the Festival of Lights for those of the Judaic persuasion. Since the Jewish calendar is based on different dates than the western one, liberal Jews can have their Hanakkuh, and still celebrate Christmas and Kwanzaa with their friends. Anyone want a convertible Hanakkuh bush? Everybody can party like it's 5775.
Kwanzaa: Created in 1966, Kwanzaa was made up by a California guy to highlight African-American culture. Cool thought, but I'd just as soon we'd say: "What? Obama is black? Wow, I didn't know that." Keeping separate ensures separateness. Hey! Doesn't that look like a Menorah?
More recently, Kwanzaa is celebrated in conjunction with Christmas since many African-Americans are Christian. I suppose those of the Muslim faith can also celebrate Kwanzaa since the major winter holy day for Muslims was way back in November.
Ashura is an Islamic holy day observed on the 10th of the Islamic month of Muharram. That was way last September, so Muslims can join in the other celebrations, or just go about your business. If you live in the US, you'll just have to put up with the constant dirge of Christmas Carols. Hey, every other group has to, so you're no exception.
As for Ashura, this is a schizophrenic holy day for the two main Muslim sects. Shi'ite Muslims regard it as a major festival marking the martydom of the Prophet's grandson, Hussein. It's a more solemn holiday involving fasting and re-enactments of the martyrdom which includes some pretty nasty self-flagellation. Nothing says holiday cheer like a bloody back.
For Sunni Muslims this is the day that celebrates the release of the Israelites by the Pharoah. Yes, the Sunnis are pleased the future Israeli people were freed from Egypt. Not sure how this squares with the current state of affairs. However, since the Biblical Old Testament is regarded holy by the triumvirate of monotheistic world religions, there has to be some crossover of beliefs.
Atheist/Agnostic/Pastafarian: The godless like holidays as much as the next person. They just don't have an official date for the FSM's birth celebration. FSM, you ask? Flying Spaghetti Monster has become the avatar for folks that think the FSM is just as realistic as any other god.
So, whatever you celebrate around this time of year, enjoy, be happy, and don't drink too much (not a problem with the Muslims and the Mormons, right?).