http://totl.net/Eunuch/index.html
he overclocked a 486 SX (dunno why he chose one of those, the DX has better floating point calculations) , maybe it was cheap
he ran it in his fridge and OCed it from 33mhz to 120mhz easialy, but then they decided to go all in and got it to 247mhz for two and a half minutes of halflife (lol)
thats like a 13 times overclock lol