I usually have to go into work for an hour or so on Christmas Eve (if it's a weekday) but everyone brings their DCs so DD comes too. DH wanders into town for a nice coffee waiting for us (I work close to the main shopping street) and then we meet him for any last minute bits we want (usually includes going into M&S to buy DD's birthday cake - not something everyone needs to do! But it's actually usually fairly OK in the city centre one on Christmas Eve, the manic day there is 23rd!).
We also look at the Live Crib outside the Lord Mayor's house for the last time (we'll have visited a couple of times before usually) before we head home.
In the afternoon, we always bake cookies for Santa. Some years, we do actually have the time and energy to make these from scratch. But I ALWAYS make a few batches earlier in the run up to Christmas, and freeze part of the log of dough so I have some I can just "slice and bake" from frozen on Christmas Eve if necessary (and we have done this QUITE a few years!!).
We usually start to track Santa on Norad in the early afternoon as well. Just have a computer on somewhere and check on progress over the course of the afternoon/evening.
I usually do try to get DD to watch a movie at some stage, to relax a bit. It doesn't always happen though.
After dinner, we have a few things that always happen.
We get out the red Christmas Candle, which is an Irish tradition to show that there is "room at the inn". The youngest in the house lights it (so DD here). In our family, following on from my own family tradition, we take a few minutes to do this all together, and have a little rememberance of all the good things that have happened in the year past, and remember all our friends and relatives who are not around to see Christmas this year (some abroad or some who have died over the years). And we do say a prayer asking for blessings (not a whole decade of the rosary like I grew up with).
Then we get out the Christmas "Hamper" - a big cardboard box. In it are new PJs for all 3 of us (DH, DD and I) - DD's are usually Christmassy, while DH and I just get nice ones. Some years there are slippers for DD, other years, just slipper socks or fluffy socks. I put my (much loved and re-used) Nightmare Before Christmas slippersocks in there too, and DH has a big pair of Elf-ish ones too. DD has a snowman cover for her hotwaterbottle, and that is first used every year on Christmas Eve so comes out of the box, and our family copy of "Twas the Night Before Christmas" for bedtime story reading. And DD's stocking. Then we are back to new stuff again - a lush bath bomb each for DD and I (she gets a properly festive one - Santa's face or similar - while I get something totally relaxing which may or may not be festive), and perhaps a nice shower gel for DH (he was not keen on the chocolate one of last year, but the hot pepper the year before was a hit!). There are 3 hot chocolates (the lump of chocolate on a spoon to melt into hot milk) - plain for DD, dark with orange or chilli for DH, and dark for me (which I adulterate with amaretto or chocolate liqueur or brandy some years). Marshmallows and squirty cream to go on top of the hot chocs. And perhaps a Christmas beer for DH, and some years a big bag of Leonidas orangettes for us all to share over the holidays.
So we put out the stocking, and the cookies we baked in the afternoon, milk, and a carrot for the reindeer. Then DD goes up for her nice bath (she's allowed all the bath toys and given extra time to slowly wind down in there, I often have a lavender candle burning in the bathroom too) and into new PJs, before coming back down for hot chocolate and a spare cookie. Then snuggling up warm and cosy in her bed with her snowman HWB, being read TTNBC, and maybe a second story, and hopefully being calm enough to actually sleep after that slow gentle wind-down.