Fun project I made back when coffeescript was the hot new thing. Uses a genetic algorithm to try and evolve a set of randomly generated rectangles into a semblance of a supplied image. Originally inspired by a blog post that I can't find now, there are many other examples out there.
Open index.html in a browser and hit "Go". The "Grab Best Snapshot" button takes the current lowest scoring (closest) image and appends it to the end of the page for easy saving/downloading.