Talk to me about Advent calendars

[marta_bee]

Toying with a story idea for a holiday exchange, and I need a gut check. How common are Advent calendars in the UK? I'm talking about the object with the twenty-five doors that you open and get a piece of chocolate each day in December. Is that even the British name for them, and are they commonly used over there? And is there any class association to them? In my experience, at least, they were always cheaply made cardboard monstrosities with waxy chocolate inside that you picked up at the supermarket for about $10. So not the kind of thing people would display who could afford better; but that may be an American phenomenon, or unique to me.

Basically: talk to me about Advent calendars, whatever associations you have of them or memories you connect with them. Brits especially, but I'd love to hear everyone's thoughts.