My strange story is that I accidentally installed FreeNAS over a Windows 7 install completely by accident.
What happened was I had a FreeNAS disc in the drive and was looking at the program for research. Then I put the project away for a while and one day I turned on the computer but didn't turn on the monitor, the computer ran a couple days with the monitor off until one afternoon I was hearing beeps coming from the computer speaker, there was some box that was pressing a key on the keyboard apparently. I turned on the monitor to a screen that was prompting if I really wanted to wipe out the drive!
I was like, UH NO, and backed out and restarted the machine, it was too late, I had already accidentally installed FreeNAS on the HDD and Win7 was gone!
Luckily this is just a "play" machine I'm using for testing stuff like this so no big deal, but still!