Blackbox for Windows is an alternative shell for Microsoft Windows. It is based stylistically on the Blackbox window manager for the X Window System, however it does not use the same codebase except for the gradient rendering code.
Although I currently don't use Blackbox anymore, I have been using it (a few years bb4win, and a few bbLean branch) for years...
Still use it. Even under Windows 8. Unprecedented configurability and weightlessness on resources gives it my choice over any other windows shell.