Randall Munroe gives us a generator to make a unique pinball machine, with more features than you can shake a stick at. You have yellow, blue, green, and red balls constantly entering, and you are supposed to direct each color to a different designated output. Balls will disappear after 30 seconds, so you can't fill up the screen. Click the wrench to see a toolbox of your device options, and scroll down because there are a lot of them. Just exploring what they do is a lot of fun, or you can find a handy guide at Explain xkcd. Yes, each ball color has different properties. What you see above is the mess I made after about ten minutes. It's nowhere near efficient- yet. I was having too much fun causing chaos with the fans!
But there's much more. Click the "view machine" button, and you'll be taken to a scrollable gallery of completed machines that are linked together, so that the outputs of those machines, or cells, feed the balls into each other. While the number varies, there have been as many as 528 cells! When you have successfully separated your balls by color, you can submit your machine to the gallery grid, although it must pass an inspection before it's included. Munroe took on this project for April Fool's Day, but it's so complicated that the launch was delayed. The machine works better on a desktop than on a phone or tablet. -via Metafilter