Can I sync Facebook events with BusyCal?
Facebook provides calendar feeds for Upcoming Events and Birthdays, which you can subscribe to in BusyCal, as follows.
Go to this page in a browser:
https://www.facebook.com/events/upcoming
On the bottom of the sidebar on the right, you'll find two links -- one for Upcoming Events and another for Birthdays. Control-click on one of these links and choose Copy Link.
In BusyCal, select File > New Calendar Subscription, then paste the URL into the Calendar URL field and click Subscribe.