"My mum told me when I was a kid that Boxing Day started off where the people would pack up boxes of food and gifts for those less fortunate than you and take them to them on the day after Christmas. Then it sort of evolved over the years to it being the day you visited the rest of your family. Christmas was for staying at home with your immediate family and Boxing Day was when you took the rest of the gifts (or boxes) to them."
From Wikipedia:
The tradition has long included giving money and other gifts to those who were needy and in service positions. The exact origin is unknown and there are some claims that it goes back to the late Roman/early Christian era. Boxes were placed outside churches to collect special offerings tied to the Feast of Saint Stephen.
In the UK, it certainly became a custom of the nineteenth-century Victorians for tradesmen to collect their "Christmas boxes" or gifts on the day after Christmas in return for good and reliable service throughout the year. Another possibility is that the name derives from an old English tradition: in exchange for ensuring that wealthy landowners' Christmases ran smoothly, their servants were allowed to take the 26th off to visit their families. The employers gave each servant a box containing gifts and bonuses (and sometimes leftover food).
So there you have the traditional versions. These days, the holiday is all about spending money. Similar to Black Friday in the States, Boxing Day is a huge shopping day. In fact, it's not just Boxing Day, but Boxing Week!!
Well, we didn't do any shopping. None at all. So there.
We spent the evening with a nice family, eating dinner and playing Scrabble. Good fun.
They even included us in their family tradition of Santa leaving extra Boxing Day presents.
This is what Santa left me: