The following device is apparently based on magnetic forces only and has no visible energy source:
Where is it's energy source?
Full video: http://www.youtube.com/watch?v=eA0b-8pqUCk
UPDATE
One of suggestions was that energy coming from heavy rod above the setup, which is lifted initially. Unfortunately, this gives us no more than
$mg dh$
of energy, which means that the energy of rotating wheel is no more than that value. Hence, on the next cycle, it will not be able to lift the rod again to the same level, especially regarding of friction, occurring in the rod-lifting mechanism.
Best Answer
When the system starts working, the round end of the iron slice on the side is on the top. This pre-stored gravitational potential energy and kind of "magnetic potential energy" is used to drive the system. The only thing one need to consider is how one can fight with friction and air-resistance so that this rotation can be sustained longer. In this case, when it is rotating, some energy are stored back into the magnetic field so that friction only takes a bit of energy away every revolution. After sufficiently long time, however, I believe it will stop.
In conclusion, this is a delicate device to fight with friction but it is not perpetual.