Once was a day parents had to do their jobs, and manually enforce the amount of time a kid spent playing on a console. Now, all they need is the GameDr.
This awful thing attaches around the outside of the your console's power plug, and claims to be tamper proof. It can be programmed to set a countdown timer, and once that countdown is up, it cuts the power.
There's small consolation in the fact you get a warning chime at both the 10-minute and 1-minute marks, but man...I was a nice kid, but if something like that had killed my Final Fantasy VII game, there would have been blood.