For me it's about the little things you experience every year, but only at that time of year.
Music is number 1. "are you hanging up your stocking on the wall....." DS loves naff christmas songs.
Choosing a tree and getting it home (we don't have a car
), then decorating it.
The food. Make mince pies. DS likes using the nutcracker, it's a pain in the butt for such a small amount of food but as we only do it at christmas, it seems fun! A giant tin of Quality Street. Hot chocolate.
Instead of buying a crap chocolate advent calendar, we have 24 tiny home-made stockings that hang above the fireplace. I put a card in each one with an activity to do that day. Some are big (go to Santa's grotto, take part in nativity play, go to Christmas fair etc) and some are smaller (watch a christmas DVD, write cards, put out bird feeders, read a christmas story).
DS also gets a reply to his letter, from Santa, that gets delivered along with some reindeer food, by the elves (they leave it in the fireplace).