Sync Calendar with BusyCal
BusyCal is OS X calendar app that provides user-friendly interface for synchronizing with different calendar servers, including CalDAV.
Click BusyCal and select Preferences in drop-down list:
Select Accounts tab. Click "+" symbol at the bottom. Select CalDAV in Server Type drop-down list. In the User name and Password fields provide your credentials. Specify CalDAV calendar URL in the Server Address field. Finally, click OK.