I'm working on an amusing mod I originally planned to use on the entire Dark Brotherhood...
It's a Ayleid (tileset) prison, run by the player. Currently there are 8 cells, 2 large arenas (or holding cells), guards, autosealing exits, and a nifty magical prisoner transfer mechanism.
You transfer NPC's to and from cells via a spell. Press the button of the appropriate cell or select the cell from a prison control scroll, and the NPC (or creature) will zap there when hit by the Cell Transfer spell... even from outside the prison. Yes, any NPC in the game can be put in this jail

The cells themselves are just depressingly bare sunken ayleid pits with a tall ledge seperating them from anything resembling freedom. Unless someone inside has superhuman leaping ability, they are stuck. No doors on the cells, just a large ledge.
No, there is no 'questioning chamber' or blood. Not even a single shackle. I'm not tryin to simulate that here - besides I suppose you could always just 'attack' a prisoner.
What else is there? Well, for one thing, you can zap two prisoners into the arena/holding cell and cast "Unreasoning Rage", a scripted spell that massively increases aggression and drops responsibility. This provokes a fight to the death within the confines of a fenced off area. Viewing area is from a high position next to the entry door.
Why'd I do this? Well, you see, I didn't like the Dark Brotherhood quests. I felt some of those people shoulda been locked up

With a new character, I'll be able to zap NPC's who I deem "socially unredeemable" into their very own jail cell, complete with a stone bed and some hay. There they can rot for the ENTIRE GAME instead of bothering Tamriel! Oh, and I can set up a few arena matches in the prison

It's possible to move creatures and such around, so you can stage creature vs npc or creature vs creatures.... but moving in creatures from another cell doesn't work very well. Most creatures are not permanent refs, so this screws things up.
I still have yet to ensure the NPC's remain in their cells while I am gone for a week or so. It's possible they may magically wind their way back to wherever their scripting wants them....
Comments? Allegations of a diseased mind on the part of the creator? Requests for an Emperor vs Archmage fight?
Surfing Ape