This is the Advent calendar I made for my sister, based on the one made for me when I was a little girl.
I don't have a pattern--I just used mine as a guide for the size and ornament ideas. Her tree is a little more free form than mine, which is a little more her, I think. And I did her ornaments a little differently. A lot of mine have sparkly sequins and stuff--I made hers a little more simply. (See, her girl has yellow felt hair instead of orange yarn.)
Other than sewing the tree, buttons, and pockets, it's all about the Alene's Tacky Glue that comes in that gold/bronze bottle. That and a really good pair of scissors!