I don't bother, and the DC are now late teens/early 20s, but up til last year they've always had an advent calendar, ranging from playmobile to tealight candles to bog standard cadburys chocolate calendar for 99p. Neither of them are very bothered by them now, but I still like to look out for something they might find interesting.
This year I've got DD2 who is still at home a herbal tea calendar as she likes a cup after college and it comes with 24 different flavours.