It all started when I was designing a few parts on my Apple Mac Mini. It seemed to be getting a little too warm with all of the drawing I was doing. So this design was born.
All that I used was a 5" PC fan and I cut the cooling unit out of foam board (it's very forgiving!)
Step 1: The Design
Step 2: Final Design
If you would like a better view of the model;
I have the drawing posted on www.CNCMENTOR.com, if you hover your mouse over the drawing, it will rotate. You can also download the drawing model itself here if you'd like to make one yourself!
Also, check it out on the 123D Gallery!
This is a very simple design, air gets sucked in from the bottom four holes, blown up onto the bottom of the Mac Mini, and out the top four holes. You could make the fan variable speed, which I think I might do to quiet it down or shut it off when not in use.