The Apache Open For Business Project is an enterprise automation software project that includes ERP, CRM, E-Business/E-Commerce, SCM, MRP, and CMMS/EAM functions. It is a foundation and starting point for enterprise solutions and can certainly be used out of the box, but is also great for creating specialized applications.
TWiki is a flexible, powerful, and simple Web based collaboration platform. It is suitable for dynamic intranets and knowledge bases, and for sharing and managing documents and collaborative projects. It resembles a normal Web site, but every page can be changed from a browser. It features automatic link generation, full text search, group authorization, Web forms, reporting, change notification, file attachments, revision control of pages and attachments, a modular templating system with skins, hierarchical navigation based on the topic parenting feature, and more. Plugins can be used to enhance the program and build groupware applications.
Bugzilla is the leading open-source/free software bug tracking system, with high-profile installations at mozilla.org, GNOME, Red Hat, and NASA, among others. It features a comprehensive set of fields, attachment management, inter-bug dependencies, email notification of changes, a powerful query interface, reporting, and Web, XML, email, and console interfaces. It can be managed entirely using a Web-based UI. The user UI is customizable using templates.
RT is an industrial-grade trouble ticketing system. It lets a group of people intelligently and efficiently manage requests submitted by a community of users. RT is used by systems administrators, customer support staffs, NOCs, developers, and even marketing departments to track issues, outages, bugs, requests, and all kinds of other things at thousands of sites around the world.