Blackbox is Yet Another Window Manager for X11R6 that arose primarily
out of the curiosity of the authors.  It's small (around 8700 lines at
the time of writing), fast, built-in rendering code, image dithering 
at 8, 15 and 16 bits per pixel and color icon support.  Blackbox is 
[mostly] ICCCM compliant.  

Homepage:  http://linux.wiw.org/blackbox/