A*(Note: ThNdl v1.0 had the live shader editor. thndl_3, which you are reading now, doesn't. Sorry)*
So far on ThNdl, I've shown you some simple OpenGL shaders, and teased you with some not-so-simple ones.
If the whole idea of shaders is new to you, you might be wondering how you can learn more about them. I think, as with most things, the best way to learn is by doing.