Prison Architect Free on GOG!

Prison Architect is a prison simulator game, where you take the role of a warden who needs to manage a new prison and keep your prisoners in check; You can be as hard or as liberal as you want when it comes to managing them! Its free on GOG for three days; till the 19th of December! Note, you do need a free account on GOG to get access to the game. 

The game has pretty solid reviews; if simulation games are your thing then you should definitely give it a shot!