The MBFramework is a PHP/MySQL/Smarty development effort that allows a developer to build web applications by clearly separating user interface, logic and database operations. Website features are developed as self contained units represented by PHP classes. A unit, or module, might be a form that allows a user to login, a complex multi-form wizard, a list displaying articles or any other part of the website that can be extracted from the whole as one single entity. Basically, everything you see on this website is represented by a module.
Even though this is a work in progress, this framework is behind several of websites: have a look at klassentreffen.at and provisionen.at to see it in action. And of course, MBFramework.com is also running on the framework that it advertises.