Interesting. My family celebrates (presents, parties) on both Christmas Eve and Christmas Day. Each family does it differently. I was about to say that people usually go to church on Christmas Day (if they go), but they have Christmas Eve services too, often late at night. Oh, and the day after Christmas Day is Boxing Day - a holiday, from times when people used to give boxes of gifts (food?) to the poor the day after Christmas. But I could be wrong about the origin there - my memories are vague in that regard.