Valve's Summer Mapping Initiative, an officially sanctioned outlet for the Portal 2 community's creativity, has come to a close. The winners -- Patent Pending (pictured above), Infinifling, and Edifice -- are available to download and play for free, in addition to a bunch of runners-up.
While we're waiting for the Valve-made downloadable content that's due out later this summer, I suggest giving the full list a perusal. Those looking for more of a challenge from Portal 2, especially, will want to try some of these out.
Valve picks new Portal 2 PC maps [Eurogamer]
Instructions on how to play the maps, courtesy of the handsome and lovely people at Valve:
1) Download the map file from ThinkingWithPortals.com.