This day is known as st. stephen's day, but it has more commonly used name. how do people call this day? when is it celebrated? :

    In the United Kingdom and some Commonwealth countries, December the 26th  
is commonly known as Boxing Day, which takes its name from the practice of giving small 
gifts to household servants on that day for their work throughout the year. 
In Ireland the holiday is sometimes called Wren Day (День Королька), where the day is observed by visiting friends and going to parties.
This day is also called  St.Stephen's Day. St.Stephen's Day is a religious holiday.
It is now celebrated less than it was celebrated 100 or 200 years ago.