A couple of MIT guys have created the 'Pavlov Poke'. It's a keyboard that will shock you through the wrist pad if you spend too much time on Facebook. Sure, it's tongue-in-cheek, but it's also Awesome! The Pavlov Poke
You could also do what I did today and just close your Facebook. My previous record is two months without going back, wish me luck!
Leaving this place is never an option though.