Evolvotron is an interactive "generative art" application for Linux to evolve images/textures/patterns/animations through an iterative process of random mutation and user-selection driven evolution. (This process is also often referred to as "evolutionary art" or "genetic art".) If you like lava lamps, and still think the Mandelbrot set is cool, this could be the software for you.
Basically the software shows a selection of algorithmically generated images. You pick one you like and the software mutates the algorithm to produce random variants. Simply repeat until bored, hopefully encountering some pleasing eye candy along the way.