Portal 2: Community Edition promises to up the game's modding potential, and it's in open beta now

Improvements to map editing, a new lighting engine, volumetric fog, and other improvements await.
TechSpot

Fan-made Portal 2 mod introduces 40 new puzzles and 8 hours of gameplay

In brief: Portal fans, rejoice! A small team of developers who call themselves Second Face Software have published a new mod for Portal 2 that adds more than eight hours of original content to the ...