Here are some links to earlier blogs on harnessing energy expended by people.
I have seen quite a number of interesting ways people around the world have found to harness this wasted energy. There have been a plethora of new products which convert the motion generated by people into usable energy.
What I have not seen are kits which can retrofit existing products or structures to convert the lost motion.
For example how about a kit which you can install on a revolving or sliding door with a docking station to charge you iPhone or iPod
This is a fertile area where once could suggest ideas and even submit to the various contests with free 3D CAD software.
Ready for some dreaming?