Tiki Wiki CMS Groupware is a full-featured, Web-based, multilingual, tightly integrated, all-in-one wiki, CMS, and groupware. Tiki can be used to create all kinds of Web applications, sites, portals, knowledge bases, intranets, and extranets. Tiki offers a very large number of features "out-of-the-box". It is highly configurable and modular. All features are optional and administered via a Web-based interface. Major features include a robust wiki engine, news articles, discussion forums, newsletters, blogs, file and image galleries, bug and issue trackers, a link directory, polls/surveys and quizzes, FAQs, a banner management system, calendar, maps, mobile access, RSS feeds, a category system, tags, an advanced themeing engine (Smarty), spreadsheet, live support, shoutbox, inter-user messaging, menu generator, advanced permission system for users and groups, internal search engine, external authentication support, and more. It was formerly named TikiWiki.
Cerb is a fast and flexible Web-based platform for business collaboration and automation. It helps you remember anything about anyone, collaborate from anywhere, deftly reply to a flood of email, automate, stay informed, capture feedback, track time, flag opportunities, manage tasks, share expert knowledge, and otherwise execute efficiently.
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.
The Ninja project is an attempt to develop an alternative Nagios GUI with the aim of being the most useful Open Source Web front end for Nagios. It improves searching and filtering and scalability. It supports templates and skins for customizing appearance, and supports several databases. You can use the components of Ninja in combination with the CGI scripts of the original Nagios Web GUI or as replacements for them.
Alchitect helps you build Web sites and Web applications with unprecedented ease. With Alchitect, the core things that you have to do for every Web application, especially those that require a database, are handled for you. This means you have more time to design the look-and-feel of your site as well as to add features to your application.
SpamCheetah is a network-level spam filtering solution built around OpenBSD greylisting, tarpit, and blacklisting. It comes with a Web interface and requires zero administration. It does not allow spam to even land in your network, thus saving you precious bandwidth. It does not have the 'false positives' problem of losing legitimate mail.
EZPX is a lightweight photoblog engine with all the features you need and a user interface you'll love to use. It can be used as a standalone photoblog application or as a Flickr agent. It features an easy installer/upgrader that notifies you when an upgrade is available, support for templates, and much more.