Few months ago, I completed the build of my RepRap Prusa i3, and decided in the process to add a fan to it.
There are several parts that can benefit from a fan, but since I'm exclusively printing PLA, I was mainly interested in cooling down the print itself. I easily found some nice fan mounts on Thingiverse, but I had some difficulties to find the fan connector of my Sanguinololu 1.3b. And for good reasons, since there is none. Well, not dedicated to a fan at least.