even though my athlon is overclocked to 2.4ghz on air only...I've heard of extreme overclockers using an inert (non conductive) liquid submersion. It's a type of mineral oil that doesn't conduct electricity. A brand called flourinert is on the market.
It's very expensive. It has to be both very pure...but also flourinert also doesn't freeze at extreme temperatures...
ermm...I suppose a good conspiracy theory is they are jacking the price to 'get ya' too.
anyway....I have no clue if the above is real, but people really do submerge their computers sometimes...I think its a tad ridiculous...I would always rather buy an amiga, than submerge my winblows machine in oil...<--see there, I do have some amiga spirit left.