It's getting hot and you desperately need a little fan to fit onto your desk. You could either go buy one or you could finally do something with that old PC of yours and tear out its power supply fan.
Apparently some fellow discovered that the quickest way to "make" a fan is to take out an old computer's power supply fan, rip out all "unnecessary bits and pieces", leave the power adaptor inside, and tada! A little fan for your desk. [Guus Oosterbaan via Unplggd]