Pushing P4 to 5.25GHz with Liquid Nitrogen
SkywalkerOS8 writes "The folks at Tom's Hardware have an article up about their attempt to overclock a Pentium 4 over 5 GHz using liquid nitrogen as cooling. A DivX video is available along with pictures of the custom copper cooling head they made."
I'm not sure, but a better use of industrial gases might be this and probably would provide more perceived results.
(speaking as an ex LOX, LH2 and LN2 piping designer, of course, YMMV)