We spend the afternoon (or an hour of it anyway) working together in the kitchen, with the radio or music on, preparing for turkey feast. Peeling veg, making stuffing, making herby butter for under turkey skin, etc. And baking cookies for Santa (which might be made from scratch if we have the time and energy, but I also make a batch and freeze half the dough earlier in December to just slice and bake if that's needed).
Our dinner on 24th is a lot of tasty (mostly cold) things put in the middle of the table and everyone helps themselves. There is always some favourite of everyone, so they won't be hungry, but also things they may not like but others do and they are allowed to taste and then decide not to eat it. (Basically, DD hated things like cooked prawns, olives, cured meats, hummus etc but DH and I loved these and rarely have them - so DD could try them but we didn't make her eat them, unlike the rest of the year when she was expected to eat everything on her plate - and now she loves lots of things she "hated"). But it's about a relaxed meal that there is little or no prep needed - maybe a few extra carrots peeled and made into sticks when doing earlier veg prep etc.
After dinner, we are on a wind down. DD (as the youngest) lights the Christmas Candle, an Irish tradition to show that there is "room in our Inn" for any weary travellers who need it. Our candle goes on the mantle over the fire, and we take the time to reflect on the year finishing, remembering the good and bad about it and to remember those no longer with us to celebrate, finishing with a family prayer (we are not a very religious family, but this is a very peaceful and meaningful ritual to us).
We then pull out the box that normally holds DVDs (a cardboard storage box with Christmassy decoration), which now holds a new pair of winter PJs for everyone (DH, DD and I), nice hot choc for everyone, lush festive bath bombs for DD and I, DD's stocking, her plastic plate and glass with Santa on them and the family edition of "Twas the night before Christmas". Plastic crockery were a second set from toddlerhood that we have kept with the Christmas decorations since DD grew into normal crockery - her everyday set covered in flowers went in the bin years ago. But they are still well loved through the Christmas season.
DD lays out her stocking, and milk and cookies for Santa, checks the santa tracker online then heads up for her festive relaxing bath and new PJs. She comes back down for hot choc, before going to bed to hear the book as her bedtime story and relax for sleep. (Well, until she was a teen she did).
Christmas morning is about the stocking and a nice breakfast - fresh OJ, freshly baked croissants (from a tube or freezer), (large cafetiere of coffee for DH and I). DD is allowed to eat any sweets or fruit from her stocking if she wants.
We used to go to mass after showers and getting dressed in nice clothes - but not last year with covid and not this year again. But we are still able to go for a walk. Most years, we have also had some extended family visits to make, but as older relatives have died and with Covid, again that is gone.
We don't open presents under the tree until we have got home from the walk (and anything else), and organised getting the turkey into the oven. As we get in, we light the fire, turn on the oven and throw in a pack of M&S party nibbles, organise the turkey, pour a drink for everyone, (may change into more relaxed clothes if we feel like it), and then all sit down together with a drink and snacks, to open presents and relax.
Dinner is about 5 or 6pm. Then DD went to bed at a normal time when younger, now just watches a movie with us after clearing up.
We try to go for a walk on 26th as well, but we also normally hold an "open house" for neighbours and family in the afternoon. Some come early for an hour, while others have family obligations but stay late into the night when they get to us. We didn't do it last year and won't again this, but in more normal times will go back to it. Drinks, easy nibbles (bowls of crisps, M&S party food or very easy snacks, not chasing around making beautiful canapes), cheerful fire and background music - and enjoying each other's company.
I have visions of playing games, but that doesn't usually work out as people can get competitive here. I got "Exploding Kittens" this year though, as something DD might enjoy as well.