Definitely try this win32 binary of the Mandelbulb program !!! It's still a prototype, but very cool already.
This program can display a camera flight and smooth morph of a 3D fractal through various powers p=1...10. The program uses the well-known z^p+c iterative formula. The difference to a 2D fractal (e.g. Mandelbrot) is that some extra transformations define the term "z^p" (raise z to the power p) in 3D space. Otherwise it is basically the 2D Mandelbrot formula with arbitrary powers chosen. Power 2 is actually pretty boring in 3D, but higher powers exhibit a lot of fractal patterns. Because of its shape in higher powers it was given the name Mandelbulb.
In spite of using OptiX it runs fine on 8800GTX (G80)
More infos here