Another brilliant idea: Programmed

Programmed is an attachment for a television that makes it so the TV only runs for the length of time a treadmill had been ran on in that day.

Theoritically, you could also run on it too watch TV as you are running. There was an episode of Simpsons that made me think of this.

Anyway, it would probably never work, but it would be a good indicator of how long to run and also how much you stay near your TV.

Maybe a couple thousand dollars worth of an idea.