I never heard of it until I saw it on this forum and now thanks to my British mother-in-law I know what it is! She said it started when the servants had to work Christmas day to wait on the rich folks, so the day after they were given the day off and allowed to box up the good Christmas leftovers from the rich people's parties to take to their families. I had no idea, how interesting. Well happy Boxing day to anyone who celebrates it!