Whim is a window manager written in Tcl that utilizes Tk, and optionally Tile.
The core logic is written in Tcl. A small C extension (pwm.so) provides necessary Xlib and Tk C function access.
Whim supports multiple desktops. Each desktop is a canvas, so you can draw many different types of things, easily! You can extend your interface as you like! It's possible to create widgets that are integrated into your desktop, for macros, or common tasks.
Whim comes with the ability to configure its behavior on the fly without editing configuration files. There is a Behavior desktop menu, and an interactive console.