HyperKeys - Unleash the power of your keyboard by letting you bind ANY action to a shortcut. It's open-source and fully extendable. You can code you own actions or use one from the community !
i3 - A dynamic tiling window manager designed for X11, inspired by wmii, and written in C.
Skippy-XD - Skippy-XD is a full-screen task-switcher for X11.
dwm - dwm is a dynamic window manager for X. It manages windows in tiled, monocle and floating layouts. All of the layouts can be applied dynamically, optimising the environment for the application in use and the task performed.
VistaSwitcher - VistaSwitcher is an elegant and powerful task management utility for Windows OS.
Openbox - Openbox is a highly configurable, next generation window manager with extensive standards support.