In Argentina, the christmas day, in the afternoon is holiday. Then, the people can prepare the celebration for the night. Theoretically, it is a religious celebration, however, lately, Christ is not so present in the celebration.
In the region of Argentina where I live, the most of the inhabitants are european descendants. They brought their customs from Italy, or Spain. And we use to celebrate the christmas similar than them, but in summer.
In Europe, our grandparents used to eat food proper of the winter station, full of calories. Meat, chocolate, nuts, peanuts, cakes, and a lot of calories. Here, in the south and into the more aggressive summer, we eat the same food they ate over there in winter.
The activities starts at more or less 5 o clock in the afternoon, lighting a fire to cook the meat, the argentinian “asado”. In english it would be a barbecue, but in facts it is not the same. The meat uses to be more than four hours on the fire, and if it is a pork, more than five hours.
At 9 o' clock we are around the table, the whole family. The whole family in argentina means grandparents, sisters, brothers, daughters, sons, cousins, and so on. Often we choose the bigger house.
The kids ask God for gifts. Here is not “Santa”, here is “El Niño Dios.” or “The Kid God”.
He comes on a donkey and he place the gifts below the tree of christmas. The kids often leave water and grass to feed the donkey.
We wait till midnight when the fireworks starts, we greet each to others, then we toast and the children go to the tree of christmas to receive their gifts, and they begin with the games often till 2am of the day 25.
The youth go to the disco, the elders go to bed, and we stay awake till we don't have more topics for conversation.
When I was a kid, we used to go to bed after midnight,  and we received the presents  the following day.
Already, the december 25th, we use to meet again to have a cold lunch with the food of the previous night, and we are together in a long meeting, playing with the kids who have the new toys.
In my house often I have a lot kids in the pool, and we are together till the night when all is over.