Portal yet, and people who have beaten it and desperately want more. (On the off, off chance you've only started Portal -- what are you doing? Stop reading the internet and go play more!) For the rest of you though, you may be able to find a couple of minutes of diversion (or solace) from Portal: The Flash Game.
Sure, this version may lack it's big brother's sense of humor and 3D graphics, but what is here actually manages to catch the Portal gameplay experience fairly well. Heck, the portals even sound the same. If you've just finished the brilliant game, this Flash outing might just bum you out more, like looking at pictures of an ex-boyfriend, or a recently-euthanized family pet. But we're more than grateful for the shot of methadone to help us kick our addiction.