If you're not that lucky, you'll still be able to download Valve's SteamOS Linux distribution sometime in the next few days. It is believed, but not certain, that this Linux for gamers will be available on December 13th.
Greg Coomer, who works in design and communications at Valve explained on the company Web site that, "We’ve had to make the difficult decision to limit our beta to the U.S. only, because of regulatory hurdles. This was not our original plan, and it means we can’t collect beta feedback from Steam customers worldwide, which is pretty unfortunate. All things considered, we’re sure it was the right decision, because the alternative was to delay the whole beta beyond the point when we’d be able to incorporate any feedback into the 2014 products. This decision only affects Valve’s 300 prototype units; the commercial versions of Steam Machines that are for sale in 2014 won’t be affected by this. More information on those will be announced at CES on January 6."
Coomer continued, "SteamOS will be made available when the prototype hardware ships. It will be downloadable by individual users and commercial OEMs. (But unless you’re an intrepid Linux hacker already, we’re going to recommend that you wait until later in 2014 to try it out.) We’ll post info soon about that. Oh, and stay tuned for the in-home streaming beta to begin soon, too!"
SteamOS also appears to need a lot of memory. The Steam Machines are supposed to come with 16GBs of RAM.
You'll also need a mid-to-high-end Nvidia graphics card. We know the top of the line Steam Machines will use Nvidia's GeForce GTX Titan with its thousand-dollar price tag. Fortunately, you'll also be able to use the more affordable Nvidia GeForce GTX 660, GTX 760 or GTX 780 cards.