I have to admit a slight obsession with the concept of
Zero Point Energy...now I am the first to admit that what eveidence there has been so far has been mostly hokum but what if...clean, free energy forever that would be pretty useful. For one of the current 'front runners' have a look here...
http://jnaudin.free.fr/meg/megv21.htm looks a pretty heath-robinson contraption but, you never know!