Radicale is a CalDAV calendar server. It aims to be a light solution, easy to use, easy to install, easy to configure. As a consequence, it requires few software dependances and is pre-configured to work out-of-the-box.
The Radicale Project runs on most of the UNIX-like platforms (Linux, BSD, MacOS X) and Windows. It is known to work with Lightning and Sunbird 0.9+. It is free and open-source software, released under GPL version 3.
For further information, please visit the Radicale Website.