My oldest will be 14 in a couple of weeks, so not as old as your children, but still not a young child. I love Christmas, even at 41, and he has grown up seeing that excitement in me. We still sing Christmas carols together throughout the holiday season. He likes to cook, so he is my baking partner. Several times during the season we will put on Christmas music or put on Christmas movies (today we watched Christmas Vacation) and bake. We also love to go get hot chocolate and drive around looking at Christmas lights. It's a great time to talk.
I take each of my children, the youngest is 7, to shop for the family, so on Christmas they are excited not only about the gifts they are receiving, but about the gifts they are giving. They put a lot of thought into what they purchase and how they wrap the gifts, so they are excited to see others open the gifts. We have the entire extended family over on Christmas Eve, so that is more of a party that everyone looks forward to each year. I know you mentioned that it's just your own family, but if you want more people there, invite friends. On Christmas Day it's just us, and we love that.
We are Catholic, so the Advent season is a special season for us. We have an Advent wreath with special prayers and canles we light each night, and both kids enjoy that. Church is extra special this time of year as well.
Both boys like to go ice-skating this time of year, too. Your kids may be too old for that, but I still enjoy it, so maybe not. I'm sure I'm forgetting things. This is my very favorite time of year, and my kids love it too, even as my oldest is becoming a teen. He still enjoys all of the family time and the traditions we have done forever. I hope you find what you are looking for. Merry Christmas!