How about metaballs ? They make for a pretty interesting demo and there is a lot you can do with shading like point lights, reflection, refraction and so on.
There is also the classic terrain + water demo, in which you can have texturing, shades, displacement mapping (for the water), reflection...

glsl demo suggestions?
I'm using dash(sh) or bash or zsh. If possible, I would prefer to put in common place.

I want to put proper PS1 settings when I interactive with shell, so these situation should be considered


login (show PS1)
su
sudo
script (Don't show PS1)


I was put PS1 on .bashrc, but it seems not always workable.
