Kids love making these.
A completed fairy door along with a door blank makes a lovely party bag gift.
We made ours from cardboard and decorated with felt tip pens and bits and bobs from the craft box. You may prefer to use plywood and paint for a waterproof outdoors version.
(Tip: make sure the ridges run vertically, that way it looks like a panelled door)
We chose a door shape with a curved top, you might want a different style.