Christmas Eve in our home has evolved every year - hubby and I had our own traditions, but now we have DS1 who will be almost 3 this year (and DS2 will be a couple of weeks old) things will evolve again!
DH usually works most of the day (gets a break mid afternoon, but is there until about 9pm) but this year he will have the full day off! Luckily i don't need to do any Christmas Day food prep on Christmas Eve as hubby is a chef so dresses the turkey at work when it gets delivered, and does the veg in super quick cheffy time on Christmas Day!
The last couple of years have started with something like Christmas tree shaped crumpets in front of a Christmas movie, then we walk to the shop to pick up any last minute food we need (usually it's only milk or bread, or a roll of ready made pastry!) , and then home to make mince pies (with said ready rolled pastry, mincemeat from a jar!). We have Christmas music on during, and usually watch a movie in the afternoon.
I used to always attend the festival of 9 lessons and carols, but since having DS, I haven't been.
We have cheese, pate & a ham for dinner (last year DS joined in with this).
We now have a Christmas Eve box with PJs, night before Christmas book, santas plate etc in.
Santa gets a mince pie, slice of Christmas cake and usually sloe whiskey.
Once all those bits are done, its bath, Christmas stories and bed for DS and then time for me (and DH when he's home) to relax with something to drink, more cheese, put gifts out etc.
DH and I always open a pressie from each other on Christmas Eve - this stems from when we got engaged on Christmas Eve.