My 5V computer case fan arrived and I was very interested to see if I could power it from the Raspberry Pi. So I turned everything off, and plugged it into the GPIO cable. I had put the case back together with this cable because that makes it easy to access the GPIO. I went to fan manufacture and found that the Red wire was 5V input, the Black wire was ground, and the Blue wire was for the frequency readings. So I used some of the recent F/F jumper cables and plugged GPIO pin 1 into the Red for power and GPIO pin 3 into the black for power. Powered the Raspberry Pi on and right away the fan started up! Success! Now to go on and figure out a way to leave it plugged in and via software be able to control when the fan powers up. And possibly try to get the Blue wire working as well.
This site http://elinux.org/RPi_Low-level_peripherals has a diagram of the GPIO pins.
First picture is the Raspberry Pi powered off… Hard to see, but the fan blades are stopped.
Next two shots are powered and show the lights on the Raspberry Pi and the fan is a blur.
I stumbled across this site today http://hypnocube.com/ and was wondering about a Raspberry Pi controlled version…. They have a kit to buy that is currently $150 for the 4x4x4 cube. Sounds as if custom programming is limited to minimal so that is a bummer. There is a video here of someone who has done this with a Raspberry Pi. His notes about it are here. And there are some videos of people running it off an Arduino. Here is the youtube link to a demonstration of some of the things an 8x8x8 cube (blue) can display. This video and others from the same channel showing what the cube can do are amazing! A tutorial can be found here on a 4x4x4 cube using an arduino.