This will keep your FaceBook calendar but just remove those annoying events that clutter your Android calendar
Open your Calendar
Find & tap on the event that you want to delete
Long-Press the Menu button until the keyboard shows
Tap the Backspace (back arrow) button & tap the option to remove that event
Gone!
Thanks to http://geekdrop.com/content/removing-specific-facebook-events-from-my-htc-sense-calendar for the answer
