Games:

BZFlag is a free online multiplayer cross-platform open source 3D tank battle game. The name originates from “Battle Zone capture the Flag”. It runs on Irix, Linux, *BSD, Windows, Mac OS X, and many other platforms.

Frets on Fire is a Finnish music video game created by Unreal Voodoo in which players use the keyboard to play along with scrolling on-screen musical notes to complete a song, and is a clone of the Guitar Hero video game series.

Peces is a program to play the traditional Tangram, game of Chinese origin. It consists on constructing shapes with some polygonal pieces. Traditionally the game has seven pieces, but there are also variations with 5,14 pieces and others.

Frozen Bubble is a superb open source rendition of the classic arcade title ‘Bust a Move’. This version features single and multiplayer modes as well as network multiplayer and level editor capabilities.

Secret Maryo Chronicles is an Open Source two-dimensional platform game with a style designed similar to classic sidescroller games.

SuperTux is a classic 2D jump’n run sidescroller game in a style similar to the original SuperMario games. The Milestone1 release of SuperTux features 9 enemies, 26 playable levels, software and OpenGL rendering modes, configurable joystick and keyboard input, new music and completly redone graphics.

Open Yahtzee is an open-source version of the classic dice game Yahtzee. It is built to work across many different operating systems and platforms.

Urban Terror™ is a free multiplayer first person shooter, that (thanks to ioquake3) does not require Quake III Arena. It is available for Windows, Linux and Macintosh.

OpenArena is an open source first-person shooter game based on the ioquake3 fork of the id tech 3 engine. OpenArena’s gameplay is the exact same as Quake III Arena - score frags to win the game using a balanced set of weapons each designed for different situations.

Warsow is a free standalone first person shooter game for Windows and Linux. It is based on the Qfusion 3D engine (a modification of the Quake 2 GPL engine), and aimed on the competitive scene, or the e-sports community.

Alien Arena a fast and frantic first person shooter that combines the best of gameplay from games like Unreal Tournament and Quake III.

Savage: The Battle for Newerth is a fantasy/science fiction computer game that combines aspects of Real-time strategy and First-person shooter into one game. The producers of the game define it as a ‘Real Time Strategy Shooter’, or ‘RTSS’. It takes place in the far future when man has (after an apocalypse) rebuilt society, but is threatened by intelligent beasts.

Sauerbraten (a.k.a. Cube 2) is a free multiplayer/singleplayer FPS, built as a major redesign of the Cube FPS. The aim of this game is to allow map/geometry editing to be done dynamically in-game, to create fun gameplay and an elegant engine

Nexuiz focuses on bringing the FPS genre back to the basics with quick, lethal battles and balanced weaponry. As of the current release there are 9 weapons and 24 official maps, as well as 15 player models, with an average of 2 skins each.

Tremulous blends a team based FPS with elements of an RTS. Players can choose from 2 unique races, aliens and humans. Players on both teams are able to build working structures in-game like an RTS.

irrlamb is a platform game, in which the player moves a ball through a 3D terrain, it involves a lot of physics and challenging gameplay!

Wormux is a free and open-source clone of the classic game Worms. The teams are styled after the mascots of various free software projects, such as GNU, Linux, FreeBSD, KDE, GIMP, OpenOffice.org, Firefox, Thunderbird, Workrave, NuFW and SPIP.

LinCity-NG is a 3D City building Simulation Game for Linux-based operating systems. It is a polished and improved version of the classic LinCity game.

FlightGear is an open-source, multi-platform, cooperative flight simulator project featuring 20, 000 real world airports, correct runway markings and placements, world scenary, accurate terrain and more.

Peces is a program to play the traditional Tangram, game of Chinese origin. It consists on constructing shapes with some polygonal pieces. Traditionally the game has seven pieces, but there are also variations with 5,14 pieces and others.

Spring is a powerful open source RTS engine, developed for Windows and Linux that allows for large scale, detailed maps and a wide ranging 3D toolset.

Freeciv is a Free and Open Source empire-building strategy game inspired by the history of human civilization. The game commences in prehistory and your mission is to lead your tribe from the stone age to the space age…

Scorched 3D is a turn-based artillery game modeled after the classic DOS game Scorched Earth “The Mother Of All Games”.

The Battle for Wesnoth is a turn-based strategy game with a fantasy theme. Fight a desperate battle to reclaim the throne of Wesnoth, or take hand in any number of other adventures.