Any of you monkeys played this?
It's great.
Runs on the half life 2 game engine, so looks lurvely.
Basically it's a first person puzzle game, you have to make your way out of various test chambers using only the portal gun, which creates a doorway from point A to B. All the while being goaded, complimented and serenaded, by a computer so insane it MUST be running windows ME.
Aledgedly, you can get it for free if you have an nvidia graphics card and download the new drivers (not checked yet since I bought it, so it may only be demos).
Highly reccomended