How much would you pay never to see another talking frog or battery-powered bunny again? To program your own all-Luke Perry channel? To add impromptu bathroom breaks to live broadcasts? Replay Networks and TiVo, creators of new digital-TV recording devices, are popping the question, working to persuade you to add yet another cube to the towering ziggurat of entertainment--cable box, VCR, DVD and video-game player--on your TV table. They say their new gadgets could just change TV itself in the process, a possibility that has the networks more than a little nervous. Lawyers have been summoned.
Personal video recorders, or PVRs...