Baïkal - Cal and CardDAV server
DAViCal - DAViCal is a server for calendar sharing.
SOGo - SOGo is groupware server with a focus on scalability and open standards.
Radicale - The Radicale Project is a complete CalDAV (calendar) and CardDAV (contact) server solution.
Roundcube - Web-based IMAP email client
InfCloud - InfCloud is an open source CalDAV/CardDAV web client implementation released under GNU AGPL (version 3.0).