AssaultCube is a fast and furious first person shoot-em up that sees you take on the role as hero in a world of villains and thugs gone mad.
AssaultCube (formerly known as ActionCube which sounded like some kind of Rubiks Cube on steroids) is a free first-person-shooter based on the game Cube. We're not talking Grand Theft Auto graphics but the developers have done a reasonable job for a free game. The limited graphics have been designed in such a way that you could even play multiplayer AssaultCube on a 56K modem so on a broadband connection, you won't experience any lags at all.
Also, because it uses the SDL library, it can be used on multiple platforms so it's suitable for users on both Mac and PC to blow each other's brains out. There no 'mission' as such - simply join one of the public servers and team up with a bunch of other players when you're prompted to and just go around destroying your opposition. For those that want to get more serious, there are leagues and cups available where the winners are those that have simply killed the most.
For a free role playing shoot-em-up, AssaultCube isn't a bad offering but the limited range of graphics and level scenarios (although there is a level editor) soon become quite boring.