SOGo - SOGo is groupware server with a focus on scalability and open standards.
SABnzbd - SABnzbd is a free/open-source cross-platform binary newsreader written in Python.
Baïkal - Cal and CardDAV server
NZBGet - The most efficient usenet downloader.
Radicale - The Radicale Project is a complete CalDAV (calendar) and CardDAV (contact) server solution.
GrabIt - GrabIt is a free application that enables you to easily find and download content from Usenet news...