My advent calendar by 2009, The Moomins and in Swedish; Mumintrollen.
An Advent calendar is a special calendar which is used to count or celebrate the days of Advent in anticipation of Christmas. Some calendars are strictly religious, whereas others are secular in content.
Today, most advent calendars are made for children. Many take the form of a large rectangular card with many "windows", one of which is opened every day during Advent. In less elaborate calendars; each window opens to reveal an image, a poem, or part of a story such as the Nativity story itself. More elaborate Advent calendars have a small gift concealed in each window, such as a toy or a chocolate item.