A simple Game Boy Camera-style filter made in HTML5 and JavaScript.
Load the page, it'll ask you if it can use your computer's webcam (if it has one). Let it. It'll show every frame from your camera as if it were coming from a Gameboy Camera.
The first and hopefully only website you'll have to visit when configuring a Linux machine to use a printer.
What to do when you see the dreaded "Call to undefined function filter_var()" error message in your Apache logs. It's actually easier that it sounds but I recommend matching the version of the PHP source you download to that installed from your distro's official package.