Our simplest Advent calendar to date, this is a minimalist take on the holiday tradition: Form the shape of a Christmas tree with envelopes in various sizes, and mark each with adhesive numbers. Stuff them with thin, lightweight presents, such as gift cards and stickers. (You can also see more of our advent calendar ideas.) Use painters' tape to secure the envelopes to the wall.
Vinyl numbers, 1 1/2", $4.25 per pack (4 of each number), and Rouge envelopes, from $5.25 for 25, paperpresentation.com. Pillows, Eep! in Cocoa, and Herds, in Deep Red; 19 1/2" square, $55 each, by Skinny LaMinx, heathceramics.com.