This is my Hackintosh/gaming PC, built inside a PowerMac G5 case with an interesting history. It was originally purchased by Microsoft in December, 2003, and was used as an Alpha Xbox 360 development kit running a custom version of Windows NT. It was then sold (or possibly rented) to EA Chicago, developers of the Def Jam fighting game franchise.
EA Chicago closed in November 2007, and from there the machine somehow found its way to Saint Louis where it eventually ended up in my possession. By this point it was largely unusable, but the case was still in good shape, so I decided to modify it into a case for my Hackintosh!
It now contains a Gigabyte GA-z77x-UD5H motherboard and an Intel i5 3570K CPU, as well as a Gigabyte GeForce GTX670 GPU. It dual boots Mac OS X 10.8 and Windows 7 from dual SSDs, and also sports a pair of 1TB storage HDDs.
I recently added a second monitor to my setup and the 670 drives both screens beautifully.