I’m just getting started with Notch so bear with my noobness please!
I’m trying to get a spot light to cast shadows. Here you can see the spot going right through the sphere. I have the cast shadows checkbook checked for both the sphere and the rings. The (spot)light has a Cast Shadows checkbox which seems to be greyed out although I can check/uncheck it (still does not help). I saw something about shadow maps in the manual but not sure where to start there… 
Hello,
To get the shadows (and many other features) working you need to turn on Deferred Rendering on the Root node. If you are doing lighting you should also try Linear-Space Lighting and HDR (on the Root).