SuperTux - SuperTux is a classic 2D jump'n run arcade sidescroller game. The Milestone1 release of SuperTux features 9 enemies, 26 playable levels. - http://supertux.lethargik.org
Stendhal - Stendhal is a multiplayer online adventures game developed using the Arianne game development system. - http://arianne.sourceforge.net/?arianne_url=games/game_stendhal
Battle for Wesnoth - Polished turn based strategy game featuring fantasy characters and modular plots. - http://www.wesnoth.org
Frozen Bubble - Frozen Bubble arcade game with colorful animated penguin eyecandy - http://www.frozen-bubble.org
Zelda2D - Zelda2D is a free Zelda alike game - http://zelda.netster.de
Wormux - Use dynamite, grenades, baseball bat and others bazookas to exterminate your opponent in a 2D toon style scenery and a funny environment. - http://www.wormux.org
VegaStrike - VegaStrike is a 3D space simulator which allows you to trade and bounty hunt just as Prevateer or Elite. - http://vegastrike.sourceforge.net/
LinCity-NG - LinCity-NG is a City Simulation Game. It is a polished and improved version of the classic LinCity game. - http://lincity-ng.berlios.de/wiki/index.php/Main_Page
OpenCity, another free 3D city simulator - OpenCity is a 3D city simulator game project written in standard C++ with OpenGL and SDL from scratch. - http://www.opencity.info
Abandoned Bricks game - Abandoned Bricks is a Tetris-like cross-platform game. Beside the classic gameplay it offers music, sound effects and a duel mode. - http://abrick.sourceforge.net
Online multiplayer poker in 3D - Poker3d is a poker server and client. The client shows poker players in a 3D scene, animated according to the state of the game. - http://freshmeat.net/projects/poker3d/