I'm not a big gamer -- and I'm really not a FPS (first person shooter) gamer. I'll pass on Quake and all of it's descendents. But, I do like puzzle games a lot. Here are two must have high-brain-function games for the Mac. Go grab these games and make sure you've got a bit of time to spare. Quinn
I've loved Tetris® ever since I first played it in junior high! The game is simplicity at it's finest, and presents the impossible challenge of infinitely fast tiles dropping down on you. Quinn is a stellar game that is not Tetris, but is a game where tiles drop down. It's awesome. I find that I enter a near trance-like state while playing Quinn. Quinn is even free, and comes with a standalone server that you can start on your local network and play multi-player games with your friends and family! Or, hop onto some of the public Quinn servers and play people around the world.
Frenzic is a new game where you place slices of pies together and try to complete them to score points. It's very similar in game play to Quinn. The game speeds up as you play, and placement can be very difficult. I'm new to this game but am already getting pretty addicted to it. It's very hard, and has a bit more strategy to it than Tetris. Frenzic isn't free, but the cost is pretty low and comes with an online ranking system.