Sci-Fi......I like a little variety to torture, here are some. (I too have a twisted mind every now and than)
Scary - Keep them alive while they carry alien based parasites. They could be ones that need their host alive, but permanently keep the victim in a paralyzed state as long as the parasites live. Keep an internal video camera inside the victims body so they could watch what is happening in them.
Funny - Have the victim survive on his/her own recycled....waste. Such tech would not exist now, but should in the future. Sorry, but only in Hollywood would the victim survive such an abuse.
Sexual - A) Have the classic "machine/CPU" do the work OR B) Give a potent "desire" drug that they would stay in a near permanent state of "heat" until the victim does the work him/herself for a few hours OR until a serum is administered. Breaking point depends on victims, but it always comes.