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).
Open-source server application packages for deployment as appliances (e.g., virtual machines) or sandboxed local installation on Linux, OS X, or Windows. Smaller application downloads are available to pair with LAMP, LAPP, and Ruby base stacks. Handy for test-driving applications.
Omeka is a free, flexible, and open source web-publishing platform for the display of library, museum, archives, and scholarly collections and exhibitions. Its five-minute setup makes launching an online archive or exhibition as easy as launching a blog.
a secure, fast, compliant and very flexible web-server which has been optimized for high-performance environments. It has a very low memory footprint compared to other webservers and takes care of cpu-load.
divide the logic of a Web site from the design. Pot can be used by "common" people just by writing some XML tags in the HTML code. It supports technologies like Cascading Style Sheets, JavaScript, animated objects, and form data checking.