Last time Christmas fell on Sunday it came out that a number of churches had decided to cancel services, which provoked some controversy. I haven’t heard of churches doing that this year, whether because they have all come to their senses or because it has become no big deal. (Does anyone know of churches that have cancelled Sunday services?)
The reason given was that if people don’t have to go to church they can spend more time with their families, and Christmas, after all, is a family holiday. Do realize that this way of thinking secularizes Christmas just as much as crass commercialism. Christmas is about Christ. Specifically, it is about worshiping Christ and receiving Him sacramentally–hence the “mass” in “Christ+mass.”
The whole point, however you conceive this happening, is to not only celebrate the gift of Christ, but to receive the gift of Christ. You don’t just celebrate the fact that people gave you presents. You open them.