If you're hankering for an Xserve, you've been out of luck since 2011. But there's always an alternative. You can make your own by squeezing a whole 160 Mac Minis into a custom rack, for instance. That's what a fellow named Steve did, and the results are staggering.
Working with a vendor to get some custom shelving, Steve got his hands on 40 special 1U shelves that hold 4 Minis each. Of course, that wasn't the only challenge. Each Mini had to be fit with a special plastic insert to insure it wasn't drawing intake air from the 159 other Minis' exhaust ports, and the door of the rack was fitted with four car radiator fans, all hooked up to a 40A DC motor controller.
The result is this impressive—if crowded—tower of power, packing some 640 cores, double the amount of the 40 Xserve setup it's replacing. While Steve's reluctant to say who he works for, he's stated on his blog that the monster is part of a huge server farm, building and testing software 24/7. How's that for a Mac hack? [Steve's Blog via Hackaday via 9to5Mac]