Boxing Day is generally celebrated on December 26th. You will find all sorts of theories to explain both its existence and name. However, the general idea found in every explanation is that it is a day to think of others less fortunate than (or in a subservient position to) one’s self.
Most people have finished exchanging gifts for whatever holiday(s) they celebrate. It’s a good time to take stock of what you have and what you actually need/want and to give some of your stuff to others. You can start the New Year with a freshly decluttered home, and rid your life of some of the excess stuff from well-meaning relatives littering your floor. Box up all of your unwanted items and give it to someone who could use it. Spend some time thinking about how your actions impact others, and make a difference in someone’s life.