What was your best/worst prison?

[FyrnSkulblaka]

Built moderately sized room inside a mountain, contained a food paste dispenser (using only human meat) and was crammed full of as many "unwanted" or "hard to recruit" prisoners as possible, I encased the room to prevent entry or escape and allowed the prisoners to go insane and brawl each other until only 1 victor was alive (the rest died from malnutrition since they where constantly incapacitated from fighting before they could eat) and would proceed to install new bionic equipment and recruit the survivor

This is such a brilliant idea! I'm totally gonna make a death pit now!

[Shurp]

If you make a 2x1 room, pop a sleeping spot, take the prisioner there, exclude the bed and make a wall, you got a 1x1 prision.

That's not a prison, that's a closet.  What are you, a San Francisco landlord?