We're all atheists, but I usually still visit my brother for Christmas. It's a public holiday so still a rare opportunity to meet up during the year. We usually just laze around, eat, drink and smoke while consuming shitty media or otherwise indulging. We're not actively making a mockery of it, it's just what we do when we have nothing to do. We even do token Christmas decorations. Like putting random christmas balls on house plants ... or putting santa hats on things.