[Lucid:]

I know! I know! XCOM: Enemy Unknown is a fantastic game; one of the best of this year on multiple lists. It's available for PS3 though I played it on the PC.

If you have a control pad that can plug into your computer (or if you're not too biased against keyboard controls) there are a lot of lightweight indie games that will run on almost anything. My husband has been playing The Binding of Isaac a lot lately, and other cool lightweight PC games include Cave Story, Braid, Super Meat Boy, Dustforce, and VVVVV.