Drupal is a modular content management system, forum, blogging and community engine. It is database driven and can be used with MySQL, MariaDB, PostgreSQL, and SQLite. Its features include (but are not limited to) discussion forums, Web-based administration, theme support, a submission queue, content rating, content versioning, taxonomy support, user management with a fine-grained permission system based on user roles (groups), error logging, support for content syndication, locale support, and much more. It is considered to be an excellent platform for developers due to its clean code and extensibility, and it can also be used as a Web application framework.
LemonLDAP::NG is a modular Web SSO based on Apache::Session modules. It simplifies the building of a protected area with a few changes in the application. It manages both authentication and authorization and provides headers for accounting, so you can have full AAA protection for your Web space. LemonLDAP::NG is a complete rewrite of LemonLDAP. All components needed to use it and to administer it are included in the tarball. However, all modules developed for LemonLDAP may not work with LemonLDAP::NG.
Redmine is a flexible project management and issue tracking Web application. It supports multiple projects, flexible role based access control, Gantt charts and calendars, news, document, and file management, feeds and email notifications, per-project wikis and forums, time tracking, custom fields for issues, time entries, projects, and users, SCM integration (SVN, CVS, Git, Mercurial, Bazaar, and Darcs), issue creation via email, multiple LDAP authentication support, user self-registration support, multi-language support, and multiple database support.
AlphaLemon CMS is a content management system built on top of the Symfony2 framework. It is designed to make it as easy as possibile to manage a Web site without requiring programming or a large learning curve, while giving developers a robust and flexible framework on which to build Web applications and distributable extensions.