b2evolution, is a multi-lingual, multi-user, multi-blog engine. It was developed to provide a free, feature rich, extensible, and easy-to-install solution for efficient Web publishing of information ranging from professional news feeds to personal weblogs. b2evo can easily be installed on almost any LAMP (Linux, Apache, MySQL, PHP) host in a matter of minutes.
FUDforum is a templatable forum with i18n support based on PHP and either MySQL, Oracle, PostgreSQL, or SQLite. It features a user/group management system, a multi-lingual spell checker, both flat and thread message views, a private messaging system with multi-user forwarding capabilities, poll file attachments, and much more. It is an extremely fast and scalable forum that can fulfil the needs of both small and large forum operators.
GroupOffice is a groupware suite that takes your office online, implementing online collaboration and CRM. It allows you to share projects, calendars, files and email online with co-workers and clients. It is easy to use and fully customizable. It also features synchronization with PDAs and Outlook.
phpMyFAQ is a multilingual, completely database-driven FAQ system. It support various database systems and it also offers a content management system with a WYSIWYG editor, an image manager, flexible multi-group and multi-user support, a news system, user tracking, language modules, templates, PDF support, a backup system, Active Directory support, and an easy to use installation script.