When the kids were little, we would have dinner then go to candle light service at church. When we got back we would reminisce about past Christmases, read some Christmas stories, open "open me first" (pajamas) presents then go to bed early.
Now that the girls are on their own we try to stick to the same traditions, but the DDs and DGSs get all their presents from us. After the boys go to sleep, Santa leaves our house and takes his presents and puts them under the boys' tree. DD1 and her family spend Christmas Day with SonIL's family, but usually come by for a visit around dinner.
There is one tradition I have that started 24 years ago when youngest DD was born and my parent's didn't get to see much of them. I put together a photo album (7) of our year for family members that live away from us. It starts with Dec of the previous year and goes through Thanksgiving of the current year. That way everyone can see what the grands, great grands, and great-great grands did all year. It has become my grandmother's favorite Christmas present. She will sit with her great-great-grands and talk about what they were doing in all the pictures. I also send smaller collections of pictures to other family members who may have missed some of the activities.