Christmas changes greatly from one country to the other because of location, weather and religion. Some people celebrate Christmas Eve, others Christmas day and for others the holiday season actually begins on Christmas day and the days leading to it are not as important.
Here in Costa Rica, we celebrate Christmas Eve with a big family dinner that includes a roasted turkey or a roasted ham or both, tamales wrapped in banana leaves, about 3 side dishes, and many desserts. After dinner children go to bed early so they can wait for Santa or Baby Jesus to leave them their presents under the tree. On Christmas day people get together with more family and eat a lighter version of the previous night's meal.
In Australia the holiday season is during the summer vacation, so they have surfing Santas and lots of outdoors activities. The most important tradition is called Carols by Candlelight where people gather to sing carols under the clear sky filled with stars. They celebrate Christmas Eve with a dinner and on Christmas day children open the presents that Father Christmas has left for them under the tree.
In China, the few people that celebrate it put up a tree called the "tree of light" which is decorated with lanterns, flowers and red paper decorations that symbolize happiness. They call it Sheng Dan Jieh, in many cities is a great excuse to decorate with colorful ornaments and Santa is considered a good luck figure.
Italy has many traditions that are deeply rooted in religion as they observe the 4 candle Advent Calendar and pray to the "presepio" or Nativity scene for nine days until Christmas. Children write letter to their parents where they express their best wishes for the season and sing carols at their church on Christmas day. This is one of the most important places for celebration for catholics, because they attend the events organized by the Vatican and ancient local churches.
Have a great day!