Section 8: Prejudice is on sale this week for your computer, the deal comes shortly after the game was finally released on the PlayStation Network. There's actually two places to get a deal on the game, Direct 2 Drive and Games for Windows Marketplace.
Direct 2 Drive is offering the game for $5.99 while the Games for Windows Marketplace is offering it for $7.49. I guess the advantage of picking it up on the latter is if you have some spare Microsoft Points to burn. Regardless of where you buy the game, it'll include Games for Windows Live for achievements and matchmaking.
Section 8: Prejudice offers a four player online co-op mode called Swarm. You can read all about it in our review. This is an amazing deal in my opinion for a solid shooter.