Amazing Bike Lawn Mowers, article by Warren McLaren on Treehugger. Too funny. I believe that when I saw one of these in some old friends yard ( you know who you are), it was called, A Redneck Lawnmower.
watering can fountain: even if you don't have a pump, it would be a fun activity for kids on a hot day. Use any watering can or even containers with holes punched (i. milk cartons, tin cans, pop bottles, etc.