New Year

In Russia (and all post-Soviet countries I think) New Year is the most important and long-awaited holiday. Okay, it is second, after birthdays.
Children love this celebration more than everyone else. And this is not surprising.
All kindergartens and schools put on special performances for children. In the middle of the hall, there is a big Christmas tree decorated with balls, garlands and other toys. On the top of the tree, there is usually a big star.
All children come dressed in different costumes. Years ago, costumes of forest animals like rabbits, foxes or wolves; heroes  from different cartoons or fairy tales were popular. More and more recently children tend to choose the costumes of heroes from comics and Hollywood films.
The most important thing in this party is to turn on the lights of the tree. But what's happening? They are not working! And they can’t. Without the magic words! All children must stand together and shout “One-two-three! Shine, the Christmas tree!” Oh! This is a miracle! All lights on the tree start to shine brightly.
Children play different games, see a special show, run and have fun. Another tradition – round dance (horovod). All children stand around the Christmas tree, take each others'  arms (or "stand arm in arm" to create a big human chain and dance around the tree.
The end is the culmination of the party (I'm not too sure what you mean here but I have tried to make it sound better in English!)
But it will be tomorrow, not today:)

 

Good work! There are some sentences that were not worded well and didn't sound like natural English but other than that you did a good job! :)