We don't report to much on Mac gaming here, but I'd like to rectify that a bit if I can by pointing you towards MacHeist and their crazy good deal going on right now. They've got all the chapters of Tales of Monkey Island available for $19.99. That is a saving of $15, and PC users can play the games too.
Crap, I just made it about PCs again. Well, how about this: along with your discounted games you get MacJournal, RipIt, Clips, CoverScout and Flow for free. These are all incredibly useful Mac Apps I am told, and would usually cost you a whole lot more to purchase separately. Sure they don't have anything to do with gaming, but you're already buying Monkey Island at a discounted price.
As if getting free stuff wasn't enough you get to be a good person too. 25 percent of the purchase price is going to go to a charity of your choosing. Now you can tell all your friends that you're cool enough to use a Mac and you're a good person. Be quick, the deal ends on Tuesday.