Regardless of belief there are things one can do without being alone. Donate time to helping others (food kitchens, homeless shelters, old age centers, etc). Bring presents to orphaned children. Ask a homeless person to dinner. Enjoy dinner with friends even if you don't pray or sing Christmas carols. Go to a Jewish synagogue or Moslem temple and see what they do during this time. Or go to a movie.

My daughters spend it with their mother (long story) so I head for my brother's place and spend it with him, his missus and his two daughters (my nieces) Have done for about 6 years now and an excellent few days it is

Drink like hell and eat like a maniac. What else there is to it?

This year my kid is with his dad for Christmas. I scheduled myself to work 2nd shift, and plan on sleeping in on the day. Maybe I'll drink too much the night before. But, not doing any of the normal holiday stuff on the day.