An arduino keyboard accessory, called Pavlov Poke, cradles the user’s wrist and shocks him if he spends too long on certain websites, like Facebook. Developed by two PhD candidates as a joke, both students admitted to spending more than 50 hours each week on Facebook, so though not entirely serious, it’s possible the two recognized a real problem. If the shocks don’t work, the system can alert phone operators to call the user and yell at him.