Taking a cue from classic PC modding, one gamer dunked his original Xbox in a fishtank full of mineral oil (minus the DVD/hard drives). And it runs 10 degrees cooler than before!
(Of course, that heat savings comes at the price of an unspeakable icky factor.)
Then again, if Microsoft had used this simple engineering trick in the design of the 360, just imagine all of the RRoDs that could have been avoided, you know, because no one would have bought the console to begin with. [Llama's Forums via technabob via DVICE]