I just recently finished / released a Portal community map (Conundrum). While you guys are waiting for SC2, and you are thinking about picking up Portal for a little bit, feel free to download and play through my map. Screen shots and download link below.
Download links:
http://myaperturelabs.com/file.php?id=328
http://www.planetphillip.com/posts/conundrum-portal-1/
http://www.moddb.com/games/portal/addons/conundrum
http://www.fpsbanana.com/maps/136436
http://www.mediafire.com/?o0mqmwzzm1w
Conundrum provides a diversity of puzzles experienced over the course of 4 chambers. The goal of Conundrum is to provide a fun and thought provoking experience for the average Portal player while still being appealing for the more hardcore Portal player as well.
Please feel free to email me at clancy.powell [at] gmail.com with your feedback! I'm always interested in what people think is fun and what needs work. This is my first Portal map and I plan on designing more in the future.