Rainlendars CalDav Implementation works well with owncloud (actual version 4.5)
I just installed the new rainlendar version (2.11) to check CalDav functionality.
Of course owncloud setup is not described in the help pages, but reading how it works with icloud gives the idea for owncloud.
@drehtuer: on the first run it didn't work either, but rainlendar gave me a hint that the empty calendar does not exist on owncloud, but a "default calendar" would exist. And that's it. Maybe you have a problem with the correct url? Look at owncloud cal, should be something like cookyr.de/owncloud/remote.php/caldav/principals/cooky/.
@Rainy: great job! Thx! !!!