A massive multiplayer space trading and combat game for Linux. [GPL]

Developer of the open source HAWK game engine, and the OpenNL portable networking library for Windows.

Shawn Hargreaves has several Open Source projects and interesting articles about the future of Open Source games.

The LGDC provides concise and accurate articles about Linux gaming news, development tutorials, and reviews of the latest tools and resources.

A fantasy RPG game available for Linux, FreeBSD and BeOS. MacOS and Windows support will come soon.

Open-source Tetris implementation.

A collection of open source client, server, and editor to build online role playing games.

Chess engine including artificial intelligence, user interface and several features.

Clone of the classic game "Paradroid". (C, Python) [MacOS, Windows 95/98/2000, Linux]

2D single player space strategy, combat, and trading game. (C++) [OS Independent]

A 2D real-time multiplayer tank battling game. (C++) [Windows 9X/2000/XP, Linux]

Danger from the deep (aka dangerdeep) is a Free / Open Source World War II german submarine simulation. [Linux / Windows] (C++)

Sekoya is a gathering of students trying to develop nice open source games. Our main project is a MMORPG running under Linux and Windows.

Free quiz game based on the "Who Wants to Be a Millionaire" game show. Add your own questions for classroom use or for fun. [Java, OS Independent, GPL]

Right Wing Smackdown Game. The game for the whole violent leftist family. For any unix command line, including OS X.

The FlightGear flight simulator project is an open-source, multi-platform, cooperative flight simulator development project. Source code for the entire project is available. (OpenGL)[OS Independent]

A web magazine devoted to open source game development.

Build games on Secureplay sourcecode libraries in Flash/Java C++. Create secure game transactions for multiplayer games (player management, state/event control, random events, secret events) Platform independent Encrypted pluggable communications.

A puzzle game based on oxyd. Runs on Windows, OS X, and most open source operating systems. (C++) [GPL]

Small apps and games developments.

Colonize Europe in this Java based, open source game. Live an adventure in the 12th century world.

Free isometric real-time MMORPG. 2d/3d graphics, 3d sound effects, digital ambient music.

8-ball pool for Linux with customizable physics.

OpenLieroX is the open source clone of the famous Liero (the realtime Worms) game.

This game is a fast paced arena sport where players try to explode the opposition using a short-fused potato bomb.

irrlamb is a 3D game that probably involves a lot of physics and frustrating gameplay. (C++) [Linux, Windows] [GPL2]

An OpenGL racing game featuring Tux, the Linux mascot. The goal of the game is to slide down a snow- and ice-covered mountain as quickly as possible.(C++,TCL) [Linux,MacOS X]

CSPoker is a lightweight poker client/server. Client implementations in Java and Flash. XML-based API. (Java) [GPLv2]

Holtz is a GPL implementation of the abstract strategy board games Zèrtz and Dvonn from the GIPF project. (C++) [Linux, Windows] [GPLv2]

The encyclopedia of free (as in freedom) games with free content.

Open source games weblog and list.