As an atheist I do not celebrate Christ's birth, especially considering I doubt such a person existed, but I do still have fun with the holiday. It's nice to have time off work and swap presents with loved ones, but of course I put my own spin on things. A couple years ago I spray painted my tree black. This year I didn't do any decorating and while I wanted to use Bible paper as wrapping paper, I just couldn't bring myself to purchase a Bible to do so.
When the supposed birth of Jesus actually happened cannot be confirmed. Christmas itself is most probably the conversion of the Pagan holiday of Saturnalia in conjunction with the winter solstice and the day Mithra's birth was celebrated, December 25th. The American celebration today makes normal activities, like going to the store, a nightmare. While on one hand it's nice for the retailers and the hospitality industry, Christmas is big business, it's also overwhelmingly busy and stressful for shoppers and workers. It's pretty clear that the celebration of Christmas isn't going anywhere anytime soon, but the initally assigned meaning of it has been lost on many over the years. For myself, as a child we had a tree, gifts, left out cookies & milk for Santa and spent time with the family... that's it.
Tonight, aka Christmas Eve, I exercised, did some reading, made pasta and am watching The Office (currently). Tomorrow, I will exchange gifts, make fun of celebrating Zeusmas, and go out dancing at The Church, good times!