Portal 2 has received ten levels of downloadable content, and you're not allowed to play it. That is, unless you throw down $140 for a new controller. Razer's Hydra motion controller is currently on sale via Steam's store, and it's the only way to obtain the game's first playable DLC -- developed not by Valve, but Sixense Studios.
Apparently, the content has been designed specifically to show off the motion controls of the Hydra, so even if you could buy it separately, it'd do you no good. It's a shame, because the DLC sounds cool, featuring portal rotation and the ability to change the size of objects.
Also, the controller/DLC is not available in Europe, because it's Friday. Well, that's as good as reason as any for all of this crap.
Portal 2 DLC Arrives, But You Can’t Have It [Rock, Paper, Shotgun]