It would seem as if Apple could make it easy to import Facebook calendars to the built-in Calendar app in OS X Mountain Lion, would’t it? I mean, you can totally import Facebook contacts into the Contacts app. Why not Facebook calendars into the Calendar app?
Well, I wouldn’t even bring it up unless I had found a solution. Here’s how to bring your Facebook calendars to your Mac.
Open Facebook in your web browser, and navigate to your events page, found by clicking on the Events link in the left side bar of your Facebook homepage. At least until they change it again. Once on the Events page, click on the gear icon in the upper right. There should be an Export option there. Choose it.
Click on the link ‘upcoming events’ in the resulting dialog, and your web browser will open Calendar. If you’re using Chrome, you may need to tell your Mac to go ahead and launch the app. Once Calendar launches, however, it will open with a dialog box open and the URL for your Facebook upcoming events calendar already pasted in it. Click on the subscribe button, and Calendar will add the events calendar.
You can do the same thing with the birthday calendars on Facebook; simply click on the export your friends birthdays link from the dialogue as above. Click subscribe, and you’ll get a separate Facebook birthdays calendar in your Calendar app. Sync your Calendar via iCloud, and you’ll see these two calendars on any iOS device that’s synced with the same iCloud account. Nice!
Source: Addictive Tips