A free (libre), open-source (GNU GPL), content management platform designed for group collaboration. Open Atrium is based on Drupal (running on Apache, with a MySQL database).
A free (libre), open-source (GNU GPL) content management framework written in PHP with support for a number of operating-systems, web-servers and databases.
Drupal made international news following the U.S. White House's October 2009 web redesign. The variety of Drupal-powered websites demonstrates the platform's flexibility. Notable examples include British Medical Journal (BMJ); Stanford Law School, and Turner Broadcasting.
Environment for collaborative research, documentation and publication about issues relating to arts, politics, free and open source software and peer based commons production
"OpenPublish is a packaged distribution of the popular open source social publishing platform, Drupal, that has been tailored to the needs of today's online publishers. OpenPublish is ideal for the implementation of a variety of media outlets sites including magazines, newspapers, journals, trade publications, broadcast, wire service and membership publications."
CiviCRM is an open source and freely downloadable constituent relationship management solution. CiviCRM is web-based, open source, internationalized, and designed specifically to meet the needs of advocacy, non-profit and non-governmental groups.
Zen is the ultimate starting theme for Drupal. If you are building your own standards-compliant theme, you will find it much easier to start with Zen ...