Clearly, this is the greatest innovation in open source ever. It's free beer.
Well, the beer isn't exactly free. It's a beer recipe, created by a bunch of half-mad Danes (is there any other kind?) in Copenhagen. They call their new recipe Vores Ol, and they've got an English-language web page explaining what they've done and why.
Essentially, they picked beer for an open source experiment partly because of the famous "free as in speech, not free as in beer" quote. Now anyone can make their Vores Ol (Our Beer), including major international breweries. But, no one can prevent anyone else from making the recipe, and any modifications to the recipe must also be made open source. The whole thing falls under a Creative Commons copyright.
There's been open source software for years, but now the really exciting work is starting. Open source manufacturing has the potential to really change the way we make everyday items. Especially if you combine open source with rapid prototyping technology, also known as 3D printing and fab labs.
Ever seen Monster Garage or American Chopper? Have you noticed how those guys can modify or rebuild a car very quickly, given the right tools? What if the tools were cheaper, almost ubiquitous, and the designs and instructions for building the cars themselves (or dishwashers, toasters, CD players) were available for free as open source plans on the Internet? How would manufacturing change if any group of moderately skilled people with enough space and a little spare time could build their own consumer goods, cheaper than current market value?
We're still a long way from there, and there's lots of time left for this vision to fizzle and die. But if it comes even partly true, it means a real democratization of the making of things, of the industrial process itself. Probably there will be two major obstacles (beyond the technological) to this change. The first will be economic: will small scale production ever be able to outstrip the advantages enjoyed by major corporate manufacturers? I think, while we may not be there yet, the answer in the long run is definitely yes. The second will be one of personal choice. If people would rather buy something and have it simply arrive, they will never develop a culture of personal construction.
More likely is an intermediate world. Look at sites like Zazzle or the Make Blog. On Zazzle, you can simply buy t-shirts or postage stamps created by other people, but you can also create your own designs, and share them with others through the site. Make Blog has so many additions, of everything from software hacks to home-made air conditioners, that it's hard to keep up with all the stuff people are sharing. Most of the stuff on Make Blog comes in the form of mods, changes to existing mass-market products.
For now, let's all raise a glass of free beer, and hope for a future of personal design and manufacturing.