Paper Airplane Target practice -- yes! Cut holes in a large piece of paper and have children aim their hand-made paper planes through. Set a certain number of tries, and give a prize to the winner who got the most planes through the holes.
Dream backyard for kiddos: Nearly buried trampoline, small wading pool and playground. Playground area and pool subject to pool upgrade or conversion to garden / water feature / backyard chill pad as the kids go tweens!