I have a bad habit of keeping multiple games going at once. I kind of chalk it up to not having a ton of time during the week to game so if I have a few that I can do in short bursts til the weekend, I'll be good. That I'm readily playing:
Call of Duty: Black Ops,
All of those are on the PC.
New DLC for Fable 3 comes out tomorrow so I might be hopping back to my 360 soon to check that out.