Being Canadian, and Canada following British Commonwealth tradition, I know about Boxing Day and was surprised to find that here in the USA it is not a national holiday.  When I first started talking about Boxing Day to SueBaby, she thought maybe there was some kind of a prize fight in Canada on the 26th. of December.  The story goes that the British Aristocracy had lots of hired help, peasants living in little English Cottages where the animals slept indoors with them.  On the day after Christmas (which was an exhausting day for hired help), the help got a day off and were sent home Christmas night with boxed up leftovers from the feasting and maybe a little Christmas bonus.  Thus was born Boxing Day.  I put two and two together, and realized this also meant a rare day for the Aristocracy, when they could have the run of their castle with no hired help watching, and could run half naked through the rooms playing with each other, or play with Christmas toys, or do some napping and eating of leftovers.  Drinking too.