Youngest in the house lights the Christmas Candle on Christmas Eve - we put ours on the mantle rather than in the window, but it's an old Irish tradition to show that there is "room in our Inn" for any weary travellers. We take a few minutes when lighting it to reflect on the year finishing, good and bad parts of it and also remembering people no longer with us.
When DD was small (until she got to primary school), she used to make the same spiced Christmas cookies for the Christmas performance for parents/party in the creche - as she got older, she was able to do more bits and by her final one, the cookies she'd made could be included in what went to creche rather than being reserved for home consumption - we had lots of very small shaped cutters (I think playdoh rather than cookies - but as long as they got a good wash before use, they worked really well) in various different shapes to make small cookies for the toddlers and there were larger ones for adults in more traditional stars and holly leaves.
We also do the "give DD a budget and take her shopping to help her buy presents for the family".
And I used to fill an empty shoebox with strips of coloured paper, sellotape and kid-friendly scissors for her to work away on her paper chains when it suited her throughout late Nov/early Dec (and they were protected against getting squashed or inadvertently thrown out in the shoebox in between sessions). The results went up in the hall when we decorated the house.
And lots of other crafts - making toilet roll santa/snowman/penguins, snowflakes from sheets of plain white paper pleated and cut carefully, glittered pine cones, lollipop stick trees.....all sorts.
And I used to print free printable colouring pictures and activity sheets from the web (Activity Village, DLTK, various homeschooling sites etc) to put 1 a day into her advent calendar along with a chocolate shape (buy the nets of chocolate santas/snowmen shapes wrapped in foil from Aldi/M&S etc for those).