The Orange Book (OpenGL Shading Language 2nd Ed) has a neat little shader demo where you render the Mandelbrot set with a fragment shader.  It's one of those "cool, but not particularly practical" examples of shader's power.

I've been adding some rudimentary "generic" shader support to OpenGLContext, so I decided I'd use that little bit of sample code to test that support... and time got away from me.  Result is quite neat, the (simple) scene allows you to explore the mandelbrot with zoom, pan, and number-of-iterations control.

10 iterations gives you a loose sketch.  127 gives you a reasonable look for the overall pattern.  At around 2500 iterations with full-screen on my laptop my video card starts to stutter pretty seriously (~1fps), but the detail is really quite nice.

Wasn't what I was intending to work on, but it's kinda cool looking :) .