Rated 5 out of 5 stars

It took me a little, but this is very cool and once setup very stable. Good job!
It's a combination of this add on
Enable a public share of your calendar.
Copy the URL of your calendar.
Follow the directions at Google Help for "Get Started with CalDAV"

You can even export your default "Home" Calendar and import it into Google.

Once you play around with the public vs private viewing it's all set. So now you can use Gcal as the host and Mac/iPhone/blackberry/PC whatever as reader clients.

This review is for a previous version of the add-on (0.6b1).