I think every calendar I’ve ever owned has identified December 26 as “Boxing Day.” We don’t celebrate it — whatever it is — here in the States, but the name of the holiday certainly is evocative.
The internet, of course, lets the us learn about these curiosities with a few taps of the keyboard. It turns out that Boxing Day is celebrated in former British Commonwealth countries and has nothing to do with Muhammad Ali, sparring partners, or sports. Instead, it is a day to give presents to tradespeople and those less fortunate — and, more recently, has become a big day for shopping. Although the origins of the holiday seem to be obscure, it apparently began with presents given by upper-class Brits to their servants. Whether those gifts were given in boxes, or whether the servants needed to remove the boxes left over from their masters’ Christmas celebrations in order to get the gifts, is anybody’s guess. In any case, you can read about Boxing Day here and here.