P4A (PHP For Applications) is probably the best PHP5 RAD and object oriented PHP framework for building event-driven stateful web applications. It is based on Zend Framework and features tableless HTML, multiple databases, accesskey support, auto data type recognition, transparent AJAX, UTF-8, i18n/l10n.

Site: http://p4a.crealabsfoundation.org/

The project was founded by Fabrizio Balliano and Andrea Giordana!