Nathan linked to a great
Dilbert.
That reminds me of my perpetual motion machine ideas from grade and middle school before I learned about this whole "conservation of energy" bullshit. Most of them involved spinning compasses with a magnet, but on a massive scale with a little bit of brushing, but not too much to prevent the spin. Others involved giant pendulums and giant magnets, so the power required to start it would be thousands of workers to pull back the pendulum. That way it didn't violate thermodynamics but still let mankind chill for a few years while the pendulum's motion died down and powered our civilization. I think that was when going over the Pyramids in history, so I think I may have been overestimating the energy efficiency of human muscles a bit.