Xoops PHP CMS

http://www.xoops.org/
"XOOPS is an extensible, OO (Object Oriented), easy to use dynamic web content management system written in PHP. XOOPS is the ideal tool for developing small to large dynamic community websites, intra company portals, corporate portals, weblogs and much more. Read the All about XOOPS page for more details.

If you are looking for XOOPS support in your own language, check out the list of International XOOPS Support websites!"