This is a total geek experiment done by few Microsoft Redmond guys. They got 4 Surface Pro devices and built a server farm in about one hour.
After that, they were just having fun and moving VM across the 4 Surface Pro devices. The key feature in Windows Server 2012 is Share Nothing Live Migration, which allows you to live migrate VMs without Cluster or share storage. If you want to try it out, here is the configuration guide.
This is CRAZY, so sit back and enjoy the cool video!