The tradition of Boxing Day began in 19th-century England under the reign of Queen Victoria, although the exact origin of its name is unclear. One theory connects it to the tradition of clergy opening the alms boxes on the day after Christmas to distribute money among the poor. Another suggests that the name came from the practice of merchants handing out boxes of food or clothing to their apprentices the day after Christmas as a sort of Victorian-era bonus. In any case, the tradition of charity remains at the heart of the holiday. It's celebrated each year on December 26 -- unless that date falls on a Saturday or Sunday, in which case the holiday takes place on the following Monday.
Many modern Brits associate Boxing Day with yet another tradition -- Christmas leftovers and family gatherings. This custom, too, can be tied to Victorian England,when servants worked on Christmas and headed home to their families the following day with boxes of the upstairs family's leftoversCooking Light, Dec. 2005