Making Noise
I was reading a number of articles about using noise for image generation. I came across this set of web slides by Ken Perlin, who pretty much invented the use of noise for surface texturing and pattern deformation. In addition to some delicious eye candy, it is one of the most succinct and understandable descriptions of the process of noise generation.
Here is Perlin's original source code for generating noise in C and an application that uses his techniques to generate clouds.