Useful device to help children and their parents gauge their level of nagging and threats regarding Christmas presents throughout the month of December. Advent calendars only very recently started to use the rather gauche method of giving you a chocolate each day. When I was a lad, you got a picture behind each window (and you were GRATEFUL for that). Advent calendars showed painted, Christmas card scenes usually liberally daubed with glitter. In my house, we seemed to accumulate many of them over the years, with the windows meticulously re-closed each time, until by my early teenage years the pictures were deeply ingrained in my memory.

Of course, in this day and age, the images are replaced with Pokemon, or whatever the latest marketable non-denominational kiddies' crazy is, there is no mention of Christmas, and the numbering system has extended in both directions to probably around mid-August to allow more chocolate-flavoured sweets to be crammed in.

Advent calendars are named after the popular early mainframe game ADVENT. Possibly.

You can probably get them with condoms in too, I'd imagine.