DIY: Soda bottle sprinkler.
cutest tire swing ever! LOVE THIS!!!
Grow beans on cotton balls to understand the growth cycle of a plant.
Great playhouse / cubby house / tree house for inner city living
Tire climb, fun for the grandkids! I also see a raised garden. Place large platters or ply wood in the bottoms, fill with potting soil or soil substitute and have at it. Would look nice with trailing plants.
Toy Car Tunnel - Build a cool tunnel for toy cars out of PVC pipe
obsessed with this chair makeover! (click through for DIY details)