Thank you Priscilla for the question and linksmų Kalėdų (Merry X-Mas)!
Although, I am witting from France, I will share the experience from my last Christmas (Kalėdos) which I celebrated in Lithuania.
There were reunion and gatherings of family members living in other cities, friends & relatives like I have experienced in other countries. Someone from the family becomes Santa and gives the gift to the people and does a role play of him. Entire family starts drinking from 24th evening it lasts until the next day evening-- so much fun!
Kaunas, where I was staying, they planted large Christmas tree and people were visiting that place. A few days before the Christmas eve, there was one live charity concert where there lots of people donated whatever they could (cloths, money etc.) for the betterment of the people who were not able to buy. It was so much of fun, as I celebrated with the family of one of my Lithuanian friends. I am writing on another Christmas eve, will update more about it soon...