For CalDAV: http://agendav.org/ http://agendav.org/ is much prettier than infCloud, but actually has it's own php-backend and mysql database. A bit heavier and

For CalDAV: http://agendav.org/ http://agendav.org/ is much prettier than infCloud, but actually has it's own php-backend and mysql database. A bit heavier and is not strictly only-CalDAV. Could be a viable solution though. For CardDAV: https://github.com/owncloud/contacts https://github.com/owncloud/contacts could be used as a frontend, since it advertises it's talking to CardDAV-backend, but it's not actually deployable as a standalone interface. It's better than infCloud both architecture-wise and UI-wise, and could be the best opensource solution available, if you're willing to adapt this frontend to stand-alone usage (or integrate into whatever you need it for)