Right click the "Upcoming Events" link on the lower right side of the page and click "Copy link address".
What we just did copies a special sort of export link which we will later paste into our Google Calendar.
In the lower left corner of the page, click the arrow next to "Other calendars" and then click "Add by URL".
Paste the link you copied above from Facebook into the box, and then click "Add Calendar".
Congratulations. Your Facebook Events calendar should now be properly imported to your Google Calendar.
I have found that the Facebook calendar does not immediately sync changes to Google Calendar. You may need to wait several hours for Facebook Events to appear in your Google Calendar