An Advent calendar is a special calendar used to count down the days until Christmas. Traditionally, it starts on December 1 and ends on December 24, the day before Christmas Eve. Each day features a small door or window that can be opened to reveal a treat, a picture, or a message. This practice helps build excitement and anticipation for the holiday season. Advent calendars come in various forms, including paper, fabric, and digital versions. Many modern calendars include chocolates, toys, or beauty products behind each door. They are popular among families and can be a fun way to celebrate the Advent season together.