Zimplit CMS - The easiest Open Source Content Management System for small web- and minisites
ApPHP AdminPanel - ApPHP AdminPanel Website Back End Script
BaferCMS - The fastest and the easiest way to edit content "in-place", while looking at the website.
CushyCMS - CushyCMS is a FREE hosted content management system that's actually easy to use, fast to setup and doesn't require programming skills.
Nibbleblog - Nibbleblog is a powerful engine for creating blogs, all you need is PHP to work.
P4A - Php For Applications - PHP5 RAD Framework based on Zend Framework.