Prison Architect has been caged up in Early Access since September 2012. After more than three years of hard time, it'll finally be let loose into society for an official release this October.
I wasn't kidding about the hard time, either. Introversion has released the Alpha 35 build of their prison management sim, greatly expanding upon the gang system. Prisoners can now form protection rackets, and gang leaders will instruct soldiers to acquire new territory throughout the prison. You can see the new system in action via Introversion's latest update video.
It's been a while since I last checked in with Prison Architect, but even then it seemed like a solid simulation. Hopefully the next few months will round out its feature set to create a brilliantly bleak look at prison administration.