If you are looking for an easy way to install over 200 quality free and open source games in Ubuntu, this is it. I've taken the time to go through the Ubuntu Software Center and pick out some of the best games it has to offer. I tried to only include quality games (yes, I left out the glamorous xBill and Bugsx). I must warn, installing these games will download up to 8GB of data from the Ubuntu repositories and depending on your internet speed, could take over 4 hours to complete. For this reason, I recommend having a reliable internet connection before continuing. To install, run the following command for your release:

Ubuntu 12.04:

​sudo apt-get install supertuxkart supertux supertux-stable teeworlds nexuiz openarena frozen-bubble neverball neverputt frogatto sauerbraten kobodeluxe tumiki-fighters sdl-ball extremetuxracer extremetuxracer-extras blobby ri-li fretsonfire maelstrom titanion gnome-games kollision warmux torus-trooper torus-trooper-pure liquidwar performous performous-tools gltron xgalaga chromium-bsu kgoldrunner parsec47 gnujump kbreakout biniax2 briquolo powermanga krank plee-the-bear funnyboat mu-cade overgod rrootage icebreaker bloboats empcommand enemylines3 blockattack solarwolf alien-arena pyracerz nikwi monsterz epiphany a7xpg kolf noiz2sa pinball holotz-castle freegish xwelltris btanks koules vodovod blobandconquer blobwars penguin-command vectoroids criticalmass trackballs orbital-eunuchs-sniper luola luola-nostalgy ktron airstrike projectl tomatoes ketm njam gnibbles enemylines7 gnome-breakout pacman pychess pioneers kmahjongg kiriki kshisen kfourinline gnome-mastermind triplea yahtzeesharp fltk1.3-games brutalchess ksudoku pybik opencity sgt-puzzles gbrainy gweled numptyphysics tremulous lightsoff palapeli amoebax enigma tworld glines colorcode berusky kdiamond kubrick fillets-ng gnect ace-of-penguins kiki-the-nano-bot pathological phlipple xword anagramarama mines.app slimevolley xmoto foobillard freetennis etw tennix torcs billard-gl openbve lincity-ng flightgear gl-117 flare beneath-a-steel-sky adonthell freedroidrpg flight-of-the-amazon-queen mana ardentryst balazarbrothers balazar warzone2100 snowballz megaglest openttd pingus smc 7kaa gnubg freeciv-client-gtk freeciv-client-extras freeciv-sound-standard open-invaders freedink lbreakout2 freecol

​Ubuntu 11.10:

​sudo apt-get install supertuxkart supertux supertux-stable teeworlds nexuiz openarena frozen-bubble neverball neverputt frogatto sauerbraten kobodeluxe tumiki-fighters sdl-ball extremetuxracer extremetuxracer-extras blobby ri-li fretsonfire maelstrom titanion gnome-games kollision warmux torus-trooper torus-trooper-pure liquidwar performous performous-tools gltron xgalaga chromium-bsu kgoldrunner parsec47 gnujump kbreakout biniax2 briquolo powermanga krank plee-the-bear funnyboat mu-cade overgod rrootage icebreaker bloboats empcommand enemylines3 blockattack solarwolf alien-arena pyracerz nikwi monsterz epiphany a7xpg kolf noiz2sa pinball holotz-castle freegish xwelltris btanks koules vodovod blobandconquer blobwars penguin-command vectoroids criticalmass trackballs orbital-eunuchs-sniper luola luola-nostalgy ktron airstrike projectl tomatoes ketm njam gnibbles enemylines7 gnome-breakout pacman pychess pioneers kmahjongg kiriki kshisen kfourinline gnome-mastermind yahtzeesharp fltk1.3-games brutalchess ksudoku opencity sgt-puzzles gbrainy gweled numptyphysics tremulous palapeli enigma tworld glines colorcode berusky kdiamond kubrick fillets-ng gnect ace-of-penguins kiki-the-nano-bot pathological xword anagramarama mines.app slimevolley xmoto foobillard freetennis etw tennix torcs billard-gl openbve lincity-ng flightgear gl-117 beneath-a-steel-sky adonthell freedroidrpg flight-of-the-amazon-queen mana ardentryst balazarbrothers balazar warzone2100 snowballz openttd pingus smc 7kaa gnubg freeciv-client-gtk freeciv-sound-standard open-invaders freedink lbreakout2 freecol

​Ubuntu 11.04

​sudo apt-get install supertuxkart supertux supertux-stable teeworlds nexuiz openarena frozen-bubble neverball neverputt frogatto sauerbraten kobodeluxe tumiki-fighters sdl-ball extremetuxracer extremetuxracer-extras blobby ri-li fretsonfire maelstrom titanion gnome-games kollision warmux torus-trooper torus-trooper-pure liquidwar performous performous-tools gltron xgalaga chromium-bsu kgoldrunner parsec47 gnujump kbreakout biniax2 briquolo powermanga krank plee-the-bear funnyboat mu-cade overgod rrootage icebreaker bloboats empcommand enemylines3 blockattack solarwolf alien-arena pyracerz nikwi monsterz epiphany a7xpg kolf noiz2sa pinball holotz-castle xwelltris btanks koules vodovod blobandconquer blobwars penguin-command vectoroids criticalmass trackballs orbital-eunuchs-sniper luola luola-nostalgy ktron airstrike projectl tomatoes ketm njam gnibbles enemylines7 gnome-breakout pacman pychess pioneers kmahjongg kiriki kshisen kfourinline gnome-mastermind yahtzeesharp brutalchess ksudoku opencity sgt-puzzles gbrainy gweled numptyphysics tremulous lightsoff palapeli enigma tworld glines colorcode berusky kdiamond kubrick fillets-ng gnect ace-of-penguins kiki-the-nano-bot pathological xword anagramarama mines.app slimevolley xmoto foobillard freetennis etw tennix torcs billard-gl openbve lincity-ng flightgear gl-117 beneath-a-steel-sky adonthell freedroidrpg flight-of-the-amazon-queen balazarbrothers balazar warzone2100 snowballz openttd pingus smc gnubg freeciv-client-gtk freeciv-sound-standard open-invaders freedink lbreakout2 freecol

Ubuntu 10.04:

sudo apt-get install supertuxkart supertux supertux-stable teeworlds nexuiz openarena frozen-bubble neverball neverputt sauerbraten kobodeluxe tumiki-fighters sdl-ball extremetuxracer blobby ri-li fretsonfire maelstrom titanion gnome-games kollision torus-trooper torus-trooper-pure liquidwar performous performous-tools gltron xgalaga chromium-bsu kgoldrunner parsec47 gnujump kbreakout biniax2 briquolo powermanga krank plee-the-bear funnyboat mu-cade overgod rrootage icebreaker bloboats enemylines3 blockattack solarwolf alien-arena pyracerz nikwi monsterz epiphany a7xpg kolf noiz2sa pinball holotz-castle xwelltris btanks koules vodovod blobandconquer blobwars penguin-command vectoroids criticalmass trackballs orbital-eunuchs-sniper luola luola-nostalgy ktron airstrike projectl tomatoes ketm njam gnibbles enemylines7 gnome-breakout pacman pychess pioneers kmahjongg kiriki kshisen kfourinline gnome-mastermind brutalchess ksudoku opencity sgt-puzzles gbrainy gweled tremulous lightsoff palapeli enigma tworld glines colorcode berusky kdiamond kubrick fillets-ng gnect ace-of-penguins kiki-the-nano-bot pathological xword anagramarama mines.app xmoto foobillard freetennis etw tennix torcs billard-gl openbve lincity-ng flightgear gl-117 beneath-a-steel-sky adonthell freedroidrpg flight-of-the-amazon-queen balazarbrothers balazar warzone2100 snowballz openttd pingus smc gnubg freeciv-client-gtk freeciv-sound-standard open-invaders freedink lbreakout2 freecol

If you know of any other great games from the repositories that weren't included, feel free to leave a comment below.