Valve send word that their free DLC for Portal 2 will arrive on October 4th. Man, I totally already said all that in the headline! Here's what I didn't say, which was what Valve said: "In "Peer Review", you and a friend will continue the story of loyal bots P-Body and Atlas as you puzzle your way through a mysterious new co-op test track and once again match wits with GLaDOS. The DLC also features a single player and co-op Challenge Mode, and leaderboards to compare Challenge Mode scores with friends and the Portal community."
In other Portal news there's more Songs TO Test by over here, and I've posted quite a special Portal fan video below. Thanks, Jeep!