How the GPU came to be used for general computation.
If a program can be broken up into many threads all doing the same thing on different data (ideally executing arithmetic operations), a GPU will probably be able to do this an order of magnitude faster than a CPU.
The Mandelbulb is an attempt to create a three dimensional equivalent to the famed Mandelbrot fractal. There’s information about the math behind the Mandelbulb, many images, links to videos and more. If you want the quick version, Wired posted a brief overview and a gallery of images.