Valve teased some downloadable content for Portal 2 recently, but now the developer has gone and spilled the potatoes on the first bit of planned DLC. It's aiming for release sometime this summer, and best of all: it's free for all platforms (PC, Mac, 360, and PS3).
The first pack will include new test chambers, leaderboards, both a single- and multiplayer challenge mode, and more. The announcement didn't specify if the new test chambers will be single-player, co-op, or both, but we imagine any solo content will be roped off from the main story.
If you haven't picked up Portal 2 yet, what's wrong with you? That is to say, check out our review for Jeff's impressions of Valve's latest brain-tickler.