Zombieface allows you to find out which Facebook friends have not been active on Facebook recently, and lets you browse their timeline and unfriend them if you no longer want to keep them as a Facebook friend. Great for cleaning up your friendlist!
NOTE: Zombieface was a final project for an HNRS202 course at my university. It is not a finished application, and was created to demonstrate certain techniques. That being said, the app should work along its basic premises.