XWiki is a WikiWiki clone written in Java that supports many popular features of other Wikis like the Wiki syntax, version control, attachments, security, and searching, but also many advanced features like templates, database and dynamic development using scripting languages (Velocity, Groovy, Ruby, Python, PHP, and more), an extension system and skinability, J2EE scalability, an XML/RPC remote API, statistics, RSS feeds, PDF exporting, WYSIWYG editing, an Office viewer and importer, and a lot more.
phlyMail is a groupware, webmailer, and PIM. It offers unlimited nested groups, unlimited POP3/IMAP profiles, quotas, an integrated address book, a calendar with multiple reminders and event repetitions, a file manager with an integrated WebDAV server, the ability to send faxes, SMS support (which lets you send SMS, get reminded of events via SMS, and get email notification via SMS), a bookmark manager, themes, and multilingual support. It uses either sendmail or SMTP to send email, and can handle MIME and SSL connections. Support for IDN (Internationalized Domain Names) is included. Through its modular design, it's easy to add completely new features as modules, which can be plugged into the system.
Pandora is a distributed system to monitor processes, performance, status, application, or operating parameters of almost any operating system. It has a decentralized management system, based on flexible user profiles, that allows the user to generate graphical reports, define alarms, and a full incident management system to operate a 24x7 monitoring team.
GreenPants is a simple blog system. The entries are organized with categories. There is an admin panel for managing the blog. Comments on the blog must be approved before being seen by the public. The administrator can edit, delete, and create entries, categories, and emoticons. The entries and the comments are marked up with BBCode instead of HTML. It is easy to translate to another language.