If you still haven't picked up the GTA IV for the PC, now might be a good time to do so. Especially since the latest patch was just released making the game slightly more playable. As you can see above Steam sale puts it at a wallet friendly $34.99. A great deal for a game with some fun, albeit short, four player co-op missions.
If GTA IV doesn't tickle your uzi, then perhaps one of the other games in Rockstar's catalogue will. The entire thing is 30% off which includes games like Bully, Max Payne (for $6.99!) and Wild Metal.