After clicking the green flag, an Advent Calender will begin the pseudo-randomly create itself on the left side of the screen, then, if it is December, it will begin to open the boxes for you, before showing a list with the amount of days left until Christmas, or a special message if it is Christmas. If it is not December, the list will tell you how many days are left before you can use the Advent Calender.
I am not too sure how the second function (if it is not December) will work because I haven't been able to test it.
