Harness the Power of Children

There are a lot of different ways to generate electricity.  The physics behind it all are pretty straight forward.  A conductive material passing through an magnetic field will generate current.  All you need is a way to move the conductive material or to move (change) the magnetic field.  Why not harness the never ending energy stream coming from our children.  You could create playground equipment, like swings for example, that would be hooked up to a battery system and as the child swings they create a current that charges the battery.  At night the lights in the park would be run by the energy generated by the children during the day.