Highly anticipated and receiving a molten hot review score (9.7!) the Portal 2 Alternative Co-Op team has just released a bunch of maps for their mod, presumably. They look fantastic and judging by the trailers on their page, incredibly polished to boot.
You can download these maps on the link below, all you need is Portal 2 installed. Happy co-oping!
http://www.moddb.com/games/portal-2/addons/portal-2-alternative-1-2-co-op-maps
