Actually, I was just curious. I don't think I've ever heard an athiest say what they do with the Christmas season. I do know a few, and most actually like getting gifts.
I'm non-religious. We always have a christmas tree, stockings on the fireplace, lights on the outside of our house, and even a nativity scene (that my parents bought back in the 1950s). We exchange gifts and usually go to Christmas eve service with my parents. It's not my thing, but I'm not offended by it. I have to be honest, I sit there and ponder the influence of mythology over people's lives. My daughter (who is 18) is also non-religious, so if it gets too over the top fundy, we usually roll our eyes at each other.
Then we come home and eat prime rib.
Most of the things we celebrate (Christmas tree, lights, feasting) predate Christmas as pagan traditions and were assimilated by Christianity. So, we don't really feel any weirdness about celebrating them.