my Charter system has my pay channels selections "on demand"...which is kinda nice. I just discovered that this comes with my subscription...I am getting to like it, but am getting close to dropping the services because I am getting what I want on Netflix...
If there are scheduled showtimes, then it isn't really "on demand", it's broadcasting. Our cable has the pseudo on demand PPV system, too. Combined with a DVR, it works nicely. I can buy the movie, record it to the DVR, then my wife and I can watch it at our leisure.
The Holy Grail is where the cable system is like a personal DVD library. You pick a movie to see and it's downloaded to you alone.