Web sites found here provide information about openly developed games which are fun and entertaining.
Regular Websites
An openly developed computer version of the Acquire board game, where players buy stocks and try to make the most profit. - Acquire
http://acquiregame.sourceforge.net/
Formerly ActionCube, this openly developed game is based on the game Cube; team-oriented and multi-player. - AssaultCube
http://assault.cubers.net/
The AtariAge website is dedicated to the Atari game system such as the 2600, 5200, 7800, Lynx and Jaguar. The website also has information on new games under development for the Atari. - AtariAge
http://www.atariage.com/
An openly developed internet version of the four-player board game Blokus; complete with FAQ, AI, and more. - Blokish
http://sourceforge.net/projects/blokish
An openly developed last player riding game based on the light cycle portion of the movie Tron; for Linux, OSX, and Windows systems. - GLtron
http://www.gltron.org/
A remake of the classic BBS Door game, Legend of the Red Dragon (aka LoRD) by Seth Able Robinson. The game's source code is licensed under the GNU GPL and is available for download. - Legend of the Green Dragon
http://www.lotgd.net/
An openly developed single player dungeon exploration game that runs on a wide variety of computer systems, including Windows, and Linux. - Nethack
http://www.nethack.org/
Nexuiz is an open source multi-player first person shooter game, based on the Quake v1 - Darkplaces engine; presently available for Linux, and Windows users. - Nexuiz
http://alientrap.org/nexuiz/
Openly developed and coded in Java, the moves of Mr. X are made by the program, while the human player makes the detective moves; works on both Windows and Linux platforms. - Scotland Yard
http://sourceforge.net/projects/scotland-yard/
An openly developed web-based version of the board game Settlers of Catan; written in Java and supports multiple simultaneous games between people and computer-controlled opponents. - Settlers of Catan
http://sourceforge.net/projects/jsettlers/
TORCS, the Open Racing Car Simulator, is an openly developed 3D racing simulator using OpenGL technologies; for Linux, FreeBSD, and Windows. - TORCS
http://torcs.sourceforge.net/
UFO Alien Invasion, or UFO:AI, is a turn-based strategy game; for Linux, Windows, Mac OSX, and licensed under GPL2. - UFO:AI
http://ufoai.sourceforge.net/