The PHP Fat-Free Framework: Slim Down Your PHP Development (phpbuilder.com)

Introducing the PHP Fat-Free Framework

The PHP Fat-Free Framework manages to pack an incredible set of features into an incredibly small code base, offering native support for caching, bandwidth throttling, and a template engine. A suite of plugins further enhance Fat-Free's capabilities, providing developers with the opportunity to integrate databases including MongoDB, process forms, generate CAPTCHAs, and manage user authentication, among other features.