Got a Mac a couple months ago but haven't really looked into getting any games for it. Any good games out there for the Mac that people would recommend?

Get Steam for the Mac! Great games, and although they're out a little later than release dates, there are some great games for a decent price. I rediscovered Portal, best thing I did.

Also, one thing to note, not all mods, if any (I can't seem to get them to work) work on the mac. So if anyone knows how to resolve this, I'd be very grateful.

Sounds good, I'll check it out. What about MMOs?

MMOs are ok, but not through Steam. One game I have gone back to recently is actually Civilisation V, which is just the bomb!

a game you can play via mac, or any other os is the free 2 play online racing manager game. it is the biggest and best racing manager that came out recently. great work done by the devs.
http://www.myracingcareer.com/r19464/ try it out. it is translated to 22 languages already. great international community, over 50 different series, different cars, european series and also us series like indy car or nascar. almost all tracks in the world are present
http://www.myracingcareer.com/r19464/