Hot to Sync Facebook Events to iCal

You can sync your Facebook events to iCal (Mac's default Calendar).
1. Login to Facebook and go to "All Events"
2. Scroll to the bottom of the page and click "Export Events".
3. Click that URL , then your browser may prompts you that it will launch your default calendar app.
4. Once your default calendar launch, you can click "subscribe".

Then it works.

P.S.
You can't update the Facebook events on your calendar app in this method. It is an one way sync.
This is the same method to publish those events to your iPhone calendar from Facebook.