There really isn't much to do at this time of the year once you've eaten, drunk and been reasonably merry. Ideally some of those hours are best spent skulking around a fairy-lit garage as the ideal way to get away from all that nonsense and do something useful, like clean a car.
Actually the last time I cleaned a car for the sake of it would put me into pre-driving licence teenage years. Unless I have to sell a car, or a grimy registration plate, I don't really bother with the sponge much. Can't see the point.
I made an exception this year because I had to do something in the garage to keep warm, so it was out with the wax and buffing cloths, which wouldn't give away my location to any member of the family keen to involve me in another bloody game of charades. And anyway, I was only going to clean a Mini, so it shouldn't have taken that long.