Leave it to the BBC for trivia you can count on:

EDOW Advent Calendar“The first advent calendars appeared in 19th-Century Germany, when various methods of counting the days between the start of Advent and Christmas Day were used. Starting on the fourth Sunday before Christmas, or simply on 1 December, the Protestant Christians would keep track of the days by making marks on their doors with a piece of chalk, which would then be rubbed off one by one as Christmas approached. Other practices then developed, including burning a candle or putting up a small religious picture to mark each day.

There is some disagreement as to when the first printed advent calendars appeared, although it is clear that they were first produced at some time in the 1900s. There are claims that a Christian bookshop in Hamburg produced a ‘Christmas Clock’ in 1902, and a newspaper in Stuttgart is known to have included an advent caldendar in its pages in 1904. However, the first mass producer of advent calendars is thought to have been Gerhard Lang, who worked at the Reichhold & Lang printing office in Munich. He released his first advent calendar in 1908 and had a steady business going which produced over thirty patterns of calendar until some time in the 1930s. The calendars would usually have 24 doors, but tended to be better-decorated than modern versions.

Soon enough, calendars were being designed with little doors or pouches which contained small religious pictures or bible extracts. Better still, some of the calendars also contained sweeties in order to keep the attention of young children. The practice escalated up until the Second World War, when paper and cardboard were rationed and advent-calendar production ground to a halt. Once the war ended, though, the production began again, pioneered by Richard Sellmer in 1946.

The introduction of the advent calendar to the USA was aided by ‘Ike’ Eisenhower, whose grandchildren took a shine to the idea. The calendar was soon adopted in other countries too, and in the UK chocolates began to appear behind the little doors as soon as rationing would allow. By the end of the 1950s, chocolate advent calendars had appeared, and by the following decade they had become widespread. They still exist today, with hundreds of different varieties appearing across the globe.”

Three of the best online are the Full Homely Divinity Advent Calendar — the Episcopal Diocese of Washington’s fifth annual 2008 Advent Calendar — and the BBC’s wonderful, musical Bach Christmas Calendar.  Bookmark each of them (or just your favorite) and check each day for a new surprise.