Sawfish is an extensible window manager which uses a Lisp-based scripting language. All window decorations are configurable and the basic idea is to have as much user-interface policy as possible controlled through the Lisp language. Configuration can be accomplished by writing Lisp code in a personal .sawfishrc file, or using a GTK+ interface. Sawfish is mostly GNOME compliant
WWW: http://sawfish.wikia.com/