Postal 2 is a first-person shooter video game by Running with Scissors, and it is the sequel to the 1997 game Postal. Both are intentionally highly controversial due to high levels of violence and stereotyping. Unlike its predecessor, Postal 2 is played completely in first-person based on the Unreal Graphics Engine. Due to its graphic nature the game has been banned in Australia and several other places.
The game levels are split into days of the week starting Monday and finishing Friday. At the beginning of each day, Dude is given several tasks to accomplish, such as 'Get milk', 'Confess sins', and other seemingly mundane tasks. The purpose of the game is to finish all of the tasks throughout the week, and the player can accomplish these tasks in any way he wishes, be it as civilly or as chaotically as possible (it is possible, if occasionally difficult, to complete most tasks without engaging in battle, or, at least, killing other people). The daily tasks can be accomplished in any order, and the game includes one task that is only activated on a certain day if Dude performs a certain action.
One of the major concepts of Postal 2 is that it is meant to be a "living world", a simulation of a tongue-in-cheek off-kilter town. Game characters live out their lives completely separate from the actions of Dude; walking around town, buying and selling merchandise, and even engaging in random shootouts with each other and the police.
Source: Wikipedia, "http://en.wikipedia.org/wiki/Postal%C2%B2," available under the CC-BY-SA License.