NPR GLSL examples

Question

I'm looking for a few NPR (Non-Photorealistic Rendering) GLSL shader examples, mostly sketch or toon inspired. Does anyone have some links? :)

Answer 1

http://www.bonzaisoftware.com/npr.html

Answer 2

Chapter 18 of the Orange Book (OpenGL Shading Language) is all about NPR in GLSL.