DarkRP - a game mode for the popular game Garry's Mod with the idea of a simulation of urban life. You could become a gangster and rob people or perhaps become a police officer to protect the town from outlaws. You could open a gun shop or a pizzeria where you sell the most delicious food in town. Or you can become the mayor and manage the city, namely the police, urban economies and licensing people. Read more here.
Modding - Advanced & Professional