This idea was not my own, but was inspired by Twitto. During some extreme boredom at work I decided to "one-up" this teeny-tiny framework and improve on it. My framework does this by allowing you to run Controller files and methods in a similar way to CodeIgniter, while Twitto only has the ability to run functions from a single file.
He includes both the code for the "framework" and an example of how to create a simple controller class to work with it. He also shows how you can get a bit more MVC with it by adding in a view layer.