Create a crafty Christmas countdown with this simple DIY Advent calendar! 1) Using a variety of stamps, stickers, twine and paper, embellish and number 25 paper envelopes. 2) Attach metal clips onto a large sheet of green paper or poster board using hot glue or glue dots. 3) Fill each envelope with a handwritten note or other small Christmas surprises. 4) Finish the piece off with a barn wood frame.