Before we had kids, my husband and I would make breakfast together (usually an omelette and French toast). Then we would open presents, which usually took a while because we would look at each thing together. After that, we always went for a long walk around the neighborhood and looked at all of the lights that were usually left on all day. We'd go home, drink hot cider or egg nog, and just enjoy each other's company. I usually made food for dinner the night before, so at around noon, I'd put the ham in the oven, and we'd eat when it was ready. So, basically Christmas was just a lazy day to enjoy each other's company, since we'd see our families on Christmas Eve.
Now that we have kids, Christmas Day is a lot more exciting! After presents and stockings, we bake Christmas cookies with the kids, watch a movie, and sneak in some time to drink hot cider while the kids play with their presents. We all go out and run around in the snow, and at night we bundle up and walk around to look at the lights.