WindowMaker
I use WindowMaker all the time, but I don't really know anything about it. Except that it's a very cool window manager for X.
The WindowMaker Homepage.

The Dock
WindowMaker has a neat feature called the Dock (and an even neater feature called the Clip), and there are now numerous useful applets you can dock there.

The following applets were all created by me. They are all dockable under WindowMaker, but also work with any other window manager (and can be swallowed).

This is wmmount-1.0-Beta1.
The WindowMaker universal mount point.
View the README: wmmount.txt.
This is wmcdplay-1.0-Beta1.
A cd player designed for WindowMaker.
View the README: wmcdplay.txt.
This is wmmixer-1.0-Beta1.
A mixer designed for WindowMaker.
View the README: wmmixer.txt.

Dockable Applications
All my other X applications are written (properly :-) so that they have application icons which can be docked under WindowMaker.
My X Applications.