Today is the first day of Advent, celebrated by many, Christian or not. I didn’t start until I married into a family which celebrates it. Our calendar looks sort of like this one and I put Hershey kisses behind each door.
Here is a primer on Advent- https://en.wikipedia.org/wiki/Advent
You can buy the calendar above by following this link- http://www.hearthsong.com/wooden-house-advent-calendar.htm?aff=10051&gclid=CPiK6aLQ0NACFQ8vaQodrAsPYQ