I've compiled a little list that has a bunch of free Mac Games that I've personally played and enjoy playing. I also want to say that these are games who aren't limited to OS X: they're also available for Windows and Linux...which is how I found most of these great games.
Since I am going to be a pilot (training starting this summer), why not have a free flight simulator? So my first game is FlightGear which is just that. I must say that this is the absolute best free flight simulator out there. http://www.flightgear.org/
Sauerbraten is my favorite free FPS. It has a HUGE array of maps to play on, multiplayer is incredibly fun, and there's always a lot of people on. http://sauerbraten.org/
SuperTux is a game that's just like Mario...only with a penguin. so if you have any idea what classic Mario is, you're going to absolutely love this game. http://supertux.lethargik.org/
SuperTuxKart is an very fun MarioKart styled game. http://supertuxkart.sourceforge.net/
LinCity is a great alternative to SimCity. http://mac.softpedia.com/get/Games/LinCity-NG.shtml
Neverball is just like SuperMonkeyBall. It also comes bundled with Neverputt which is the best putting game that I've used on my Mac (unfortunately, it's PPC only, so it's not able to run on OS X Lion). http://neverball.org/index.php
Last on my list is X-Moto. It's a 2D side-scrolling game where you are a driver on a dirtbike, and you complete the levels by getting the gears. The level is complete after you get all of the gears and go to the sphere (it'll make more sense when you play it). I should also add that this game has over 2500 levels that are user-made that you can play on (after waiting for it to download). When you first download it, it comes with 305 levels, so even without getting newer levels, you still have a lot to choose from. http://xmoto.tuxfamily.org/
This isn't even close to the immense number of great free Mac Apps that there are, but these are my favorite out of the bunch.
Dec 04 '11 at 18:55