Overclocking HSF

Looking at some of the topics on this board, I read the wrong thing sometimes. So that got me thinking: has anyone overclocked their actual heatsink and fan? I guess lapping could be considered overclocking (in the broad sense of the word), but has anyone done anything more? I wonder what could be done to "overclock" the HSF. Maybe some real work, with little benefit, like texturing the fins, or even glueing (with thermal epoxy of course) extra pieces to the heatsink?

There are plenty of people out there that cram bigger fans onto their heatsinks with ducting and the like. Not sure exactly what you are looking for, thats more along the lines of "modding" than "overclocking".

Overvoltng fans, as in this front page article, would count as overclocking I suppose.