I’m not sure if anyone has posted this before, but check out this non-blender project with lots of GLSL going on:
I know a lot of similar shaders have already been demonstrated in blender, but there may be some new ones there. Notice they post their source code as well.
What really struck me is the water reflections. Blender is getting closer and closer to this, but not quite there. Yes, we have cube map reflections and mirror video textures now:D, but I think those have limitations that keep them from handling a large water scene like this.