"Boxing Day is observed only in is observed in the United Kingdom, Canada, Hong Kong, Australia, New Zealand, South Africa and some other Commonwealth nations. In America December 26 is known as the Day after Christmas Day, and is observed as a holiday in only a few states."
Its origins are considered to be in Britain with the "Christmas-box" to servants and tradespeople for good service in the previous year.
The New York Times, in a witty satirical December 2013 article, says that: "Americans observe the day by staying home with their families and staring glassy-eyed at their empty Christmas-present boxes. This is an American form of meditation and, if possible, should not be interrupted. Families do not get dressed or answer the phone, and some put trash bags over their windows and doors so that light cannot enter their homes."
"One person you will surely run into is the pizza deliverer. Today, it is a tradition to eat things that are, of course, boxed. Pizza, candy, and some types of wine are popular, as is boxed food called “takeout,” which, in America, only sometimes refers to food that is “taken out” of a restaurant—in other words, fetched by the purchaser. More often, “takeout” means “delivery.” Listen for the American idiomatic phrase “Let’s get takeout for Boxing Day,” followed by “Someone call for pizza.”
All banks and government offices are open, but the workers are grumpy. Expect short queues (or “lines”) but bad service, as most employees would rather be home staring at their boxes. To break the ice with an angry American—who, we should note, is probably not carrying a concealed weapon, no matter what you hear on the news—make small talk, and do not ask why he has worn his pajamas to work."
For me, this is the "Unofficial end to Christmas music" day. We've been listening to versions and variations since October in our retail environments, and since the beginning of December on our various airwaves. And now it goes silent for another year. Only a few songs endure between Christmas and New Year's. "What are you doing New Years Eve" a jazz standard written in 1947 by Frank Loesser.