DD's birthday is 26th December. From her very first Christmas, she helped me to make cookies for home and creche - at 11 months, it was mostly holding the spoon with me to stir the mixed spice through the flour and play with a handful of dough. Next year, she was able to whisk the egg and roll out a handful of dough, cutting a few shapes which were reserved for DH and I to eat, and as the years went on, she got better at being involved (and has been baking solo since about 13 quite happily, now a mid-teen). We used small cookie cutters and clean playdoh cutters in different shapes for cookies for the creche christmas party every year.
On Christmas Eve, she still makes cookies for Santa. This is a more slice'n'bake type dough, not roll and cut shapes one. We're all in the kitchen anyway in the afternoon, cleaning veg, making stuffing etc and generally preparing for Christmas Day, so we used to do these together and DD still makes them now. But my cunning trick was to always make sure we made a batch earlier in November/early December and freeze half that batch uncooked. So if we had time and energy, we could make them from scratch on 24th, but if that wasn't really ideal, I could take out the frozen dough to just slice and bake but still keep the tradition.
In early December, I also used to give her a shoe box filled with strips of different coloured papers (I just cut a few sheets of different coloured A4), and a roll of sticky tape. Under 1, we worked on making paper chains together, but by her 2nd Christmas, it was something I could get her going on as I started dinner in the evenings etc. Putting them back in the box once done each day protected the part done chains, and meant she could make decent length ones for the hall and her room over the course of odd-5 minutes of time throughout December.
We also have a fabric advent calendar with little pockets - I always got nets of little chocolate figures to put in there (Aldi and M&S were good for these) for each day. But I'd often print out a christmas colouring page or activity sheet from free websites, general craft ones, christmas themed ones and homeschooling ones with winter themes - one rolled up in the morning was something she could do then or later. And over the years, the same thing could evolve into more complicated pictures and writing sheets and maths sheets and quizzes that she saw as fun stuff, not school stuff.
I also have a box of christmas books, short picture stories, longer wordier books, and a couple of anthologies, (and there used to be some activity books), and some seasonal DVDs, that we take out in December for daytime watching, bedtime and other reading etc.
Christmas Eve, invariably DD came into work with me for a couple of hours while DH had a quiet coffee and ramble on the nearby main shopping street. Then we would all meet up, get any last minute bits we wanted (including going to M&S for DD to buy her birthday cake), have a nice lunch (sambo and coffee type meal), a final visit to the Live Crib outside the Lord Mayor's House, before heading home to do the prep and start the wind down. I've already mentioned the cookies while we prepped with music going.
Dinner is what we call "Platter" - lots of sliced cooked and cured meats (ham, salami, parma ham, proper corned beef etc), prawns and smoked salmon, pate, breadsticks and dips, crackers and cheeses, olives, cherry tomatoes, carrot sticks etc. laid on the table for everyone to pick what they want. A mix of things we like and eat regularly, and seasonal treats.
After dinner, the youngest in the family traditionally lights the Christmas Candle, to show any weary travellers that while the Inns in Bethlehem may have been full, we will take in any in need (Irish tradition). So DD lights the candle, and we have a family reflection on the good and bad in the year just finishing, and remember those no longer with us before finishing with a prayer.
Then DD gets out the Christmas Eve Hamper, containing new PJs for all, lush festive bath bombs for DD and I (and sometimes a nice shower gel for DH), posh hot chocolate, DD's stocking, her plastic glass and plate with Santa on from toddlerhood, snowman covered hot water bottle, and family copy of "Twas the Night before Christmas". So a mix of old and new things, some are used all winter (HWB), or advent/Christmas (plate/glass), while some are just for Christmas itself (stocking, book).
DD lays out her snack for Santa and stocking, goes up for a warm relaxing bath and into new PJs, back down for hot choc snuggled on the couch, and then up to bed with her HWB where TTNBC is her bedtime story. So it is a slow, relaxed wind-down to bed and sleep - which has always been important in our house. DH and I also tend to have a quiet evening as we are normally shattered by that point of the year.
Christmas morning involves opening stocking before a nice breakfast, hot showers, out to mass, visiting a few extended family near us, before coming back to cook a turkey and have a relaxed evening opening presents, eating a nice dinner and watching a movie together.
Boxing Day, long walk once we are up in the morning, followed by cleaning the house and having an "open house" in the afternoon for neighbours, friends and family to celebrate the season and DD's birthday. Which is officially 3-6, but regularly finishes up sometime in the early hours (as we are a sociable street).
If we travel "down home", we often arrive there on 24th, rush around both houses then, try desperately to get unpacked and organised, try and relax DD for sleep, run around between mass with 1 family (could be either), full turkey lunch in 1 house and full turkey dinner in the other house, with presents in both houses between the meals and rushing to get to both and offending everyone by not staying long enough, and then waddling back to where we're staying ......doing something to celebrate DD's birthday with everyone on 26th but spread across the day to accomodate the various other family visits involved for ILs on both sides, and head home exhausted on 27th.