Crabgrass is social networking, group collaboration, and network organizing Web application. It consists of a solid suite of group collaboration tools such as private wikis, task lists, a file repository, and decision making tools. Work is currently being done on a large user interface overhaul, better social networking tools, blogs, and event calendars, as well as better support for collaboration and decision making among independent groups.
Shapado is a multi-topic and multi-language question-and-answer Web site service à la StackOverFlow where users can vote on questions and answers and receive karma. Unlike StackOverFlow, people can ask questions on various topic by picking a category (science, programming, business, politics, etc.). It is also possible to subscribe to categories or groups of categories.
Refinery is a Ruby on Rails content management system for small business sites where the client needs to be able to update their Web site themselves without being bombarded with anything too complicated. It is truly aimed at the end user, making it easy for them to pick up and make changes themselves.
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.