For free? I know, that's pretty rare especially when its DLC(Downloadable Content). It's not those useless free DLC that gives extra clothing for your character or an item that will most likely be useless in the next few hours, this is actual content that Valve wants to give for free. Thanks Valve.
The DLC called "Peer Review" will be out on Wednesday next week or Thursday for gamers in Asia. It was announced in Portal 2's official blog. The post is mainly about the game's soundtrack, and after 2 paragraphs about it they mention the new DLC coming out soon and for free. It will include new test chambers, leaderboards, plus single player and multiplayer challenges. How many extra test chambers or challenges? They didn't say, but content is content, especially when its free.
Got Portal 2 on my PC, so I guess I'll be playing it again next week.