Now it's free, free, oh glorious free! And not just for PCs, but also for Macs. It was originally part of Valve's The Orange Box bundle, then later a $20 standalone game. IGN called it 'quirky, clever, polished, and presented with a spark of a subtly evil humor.'

GameSpot awarded it a 9.0 and an Editors' Choice. In case you're not familiar with it, Portal is regarded by many (myself included) to be one of the best games of all time. Update #2: Steam tech support just tweeted this fix: 'Please install the Steam client and try creating the account that way.' Reader Robert reports that this worked for him! I'll update further if I learn anything more. My only suggestion is to keep trying, as I'm sure Steam's servers are overloaded. Update: Many readers have reported difficulty signing up for a Steam account. Specifically, from now until September 20, you can download Portal (PC and Mac) absolutely free. Just days after I finished playing Portal for the very first time (more on that in a bit), Steam is offering the game absolutely free. One of the best PC games of all time just got better-because it's free.