I subscribe to a number of third-party calendars in my own Google Calendar, one of which being my Facebook events. However, there are a couple of issues to work around to get everything working perfectly.
If a friend has marked an event as “private”, Google Calendar only shows free/busy information because the iCal event has CLASS:PRIVATE.
A number of helpful scripts exists to solve this, simply by changing the CLASS field to PUBLIC. Make Tech Easier points to Event Busy Fix, but unfortunately this doesn’t work in Google Apps. My solution came from an answer on WebApps.SE, which suggested iCal Stripper. Here’s how to do it:
Open up your Facebook Events page.
Click on the dropdown and select “Export Events”:
Copy the link and take it over to iCal Stripper.
Grab the stripped iCal URL and add it in Google Calendar:
And you’re done!