Twitto is the smallest and fastest PHP Web framework, and the first one to use the newest features of PHP 5.3. Packed in less than 140 characters, it fits in a tweet! Despite its size, Twitto is bundled with a default controller, is E_STRICT compliant, and generates an error if you try to access a controller that does not exist.

It was developed by Fabien Potencier (of symfony framework fame) as a part of the 140 Characters Webapp Challenge