Grabbing our attention this afternoon, Valve Software has announced that they're working on a new DLC pack for their critically-acclaimed puzzle game, Portal 2. Due out on October 4th, "Peer Review" will offer a new co-op test track, along with a new singleplayer/co-op Challenge Mode and leaderboards. To celebrate this news, Valve has released the final installment of the Portal 2 soundtrack "Songs to Test By". Grab it while it's hot! :D