I used icewm some time ago, and then quite recently when putting together a dashboard of sorts. Configuration you can do in IceWM is amazing, let's you do cool tricks with your window setup.

Also it is my default WM when for some reason I want to run a browser in Xvfb and access it via VNC. Not that I've done it a lot (don't tell anyone). Running an automated browser WM-less gets annoying in certain situations.