MacOS – OS X Calendar – view shared Google calendars

This is a common error. The iCal auto setup has created an incorrect address for you. There should be no "slash" / at the end of the address i.e. it should be

/calendar/dav/youremail@domain.com/user

To fix it, go to Preferences / Accounts and change the address, removing the final / from the Server Path setting.

AFAIK Lion no longer has this bug.

I actually fixed my problem by deleting and re-creating my user account. I chose to keep the home folder in place and used it as an existing folder when I created the replacement account.

While I was troubleshooting everything I was monitoring the logs and saw no error specific error messages. The only thing that looked suspicious was a message about CalendarAgent returning status 4. I wasn't able to find a reference for that status message.

If I understand it correctly, the problem would had to have been in the /var/db/ directory in order to get fixed by an account deletion.