WindowLab is a small and simple window manager of novel design, based on aewm.

It's click-to-focus, shares its window depth policy with the Amiga, and has
a window resizing/reshaping method similar to that of 8/5 from Plan 9.
WindowLab maintains the illusion of direct manipulation by constraining the
mouse pointer when appropriate, ie when a window cannot be dragged any further
in one direction.  The pointer is also constrained vertically (effectively
making the target menu items infinitely tall according to Fitts's law) when
it's in the menubar to reduce pointing time.

Homepage:
http://nickgravgaard.com/windowlab/
