I used fleece, buttons for the eyes, small microsuede squares (to make it a diamond back) and, of course, beans.
It was so easy:
First I sewed on 4 triangles and 2 button eyes. Then I sewed the bottom, leaving the mouth open.
After I filled it most of the way with beans, I turned it so the mouth would face forward and sewed it closed.
There you have it. A ten minute bean bag snake. It fits great in the window and a certain little boy loves it - so much so that the snake slept with him in bed it's first night home.