The spiral reel lawnmowers ("Leave it to Beaver" type) are and quiet economical but a pain in the butt to use. I plan to affix bicycle pedals and a flywheel to it. I could then plop on one of my children to power it. I mow until the child gets tired and throw on a fresh one. An additional benefit is that it tuckers out the kid so they nap.-- DevoutOccamist, Feb 14 2008 Halfbakery: Kiddie Mower Kiddie_20MowerSimilar approach, but pushed, not cycled. [jutta, Feb 14 2008] A big "hamster wheel" would be better. Attach a generator to the axle, then you can split the power between cutting and propulsion.-- 8th of 7, Feb 14 2008 random, halfbakery