In Serbia Christmas eve is called Badnje veče, it derives from a word Badnjak, which means an oak branch.
(The custom is to bring an oak branch into the house and place it on the fire
on Christmas, there is even organized oak bonfires outside churches)
On Christmas eve families gather around for dinner and many don't eat food that comes from animals because its the last day of Christmas fast.
If you didn't know in Serbia the main Church is Orthodox and we still use
the old Julian calendar so Christmas is not on 25th December but on 6th January.
Here's a photo I took last year on Christamas day, in the street outside my house.

Snow snow snow :)