Fractal Art is an open source tool which creates a random piece of fractal art and sets it as your wallpaper.

The good: it's very simple. There's no graphical interface, just run the program, it generates a new image and updates your wallpaper immediately. Run it again if you don't like the results, or add it to your startup folder to get a new picture every time you reboot.

The bad: the images are very similar, mostly near-identical patterns of lines at different rotations and positions.

What might save Fractal Art for some is the way these lines are drawn. They're not plain or geometric, but instead have a far more painted look, textured, irregular and with nicely balanced (but also very varied) colour schemes. Click the thumbnail for an example.