Personally, when I think of discipline, I think of torture and pain. That's why I like this wrist strap that administers small shocks on specific commands. This product claims it can "improve your PC skill" through the administration of said pain. Apparently the BuzzTrainer software that is included is able to be bind to almost any type of PC command to administer shocks. One prime example would be looking at porn on the computer. Unfortunately, for porn fans, myself included, adding shocks into the mix may make it more enjoyable.
BuzzTrainer USB Shock Therapy Gadget [the adventures of teapot the cat]