blueyes80 open source

Frets on Fire is a game multiplatform (Windows, Linux and Mac OS X) clone of the famous Guitar Hero, where players use the PC keyboard to play musical notes of guitar flowing on the screen in order to compose a complete song.

The notes appear on the screen synchronized with the song, [...]

Urban Terror (UrT, UT, Q3UT3) is a total conversion of Silicon Ice completely opensource, Quake III Arena, developed by id Software. It introduces many elements from first-person shooter and tactical teamwork.
In this mod realism was introduced by a large number of changes. The weapons are from [...]

Tremulous is an open-source game that combines elements of an FPS than an RTS. Players can choose between two races, aliens or humans. Players from both teams can build functional structures during the game, just like in RTS games. These structures may have different functions, the most 'important [...]

Giveaway of the day can get free commercial software and games: every day there is an application and a new game, download and register for free only within the next day.
Here are the links: Giveaway of the Day Game Giveaway of the Day.
Source: Wintricks.it

Released version 0.6.0 of OpenArena, a 3D free / open source that falls within the category of "shooter", much like "Quake 3 Arena" but still under development. Finally the "bots" (robots) have been implemented and are incorporated new characters. E 'can also play online with other "human".

Nexuiz is a 3D shooter, available for Windows, Mac, and Linux. The first version was released on 31/05/2005, entirely GPL and free. Can be bred to play in both standalone and online. The latest version 2.1 is freely downloadable from here.

OpenArena, a 3D free / open source that falls within the category of "shooter", much like "Quake 3 Arena" but still under development. For example, the "bots" (robots) have not been implemented yet. E 'can still play online with other "human".