Many desks have large cupboards that may be the perfect place to store your PC tower, or, more often, your laptop hooked up to an external monitor. The problem is, it can get pretty hot back there without adequate ventilation. IKEA Hackers reader Jesper solved this problem by installing some old PC fans into the desk itself to keep his computer cool — all it requires is a little bit of woodworking.
He recommends short-circuiting a power supply and using that to power the fans, but that just seems like overboard to us. You could give it a try, but you could also get good results by converting them to USB power as shown in this DIY laptop cooler. Hit the link to read more.