MakerBot Industries was one of the first companies to dabble in open source DIY 3D printers. Anybody could download the files and make the parts that made up the printer. Since then, MakerBot has turned to pre-assembled 3D printers that they sell on the cheap. Fortunately, others have moved in to provide new open source 3D printer designs.
The latest DIY 3D printer is called the Eventorbot. The design is completely open source and it's relatively cheap to boot. It's built out of steel and a few 3D printable parts. You can obtain all the parts right now from Thingiverse.
Of course, not everybody has access to a 3D printer to make the parts. For those people, the team behind Eventorbot is hosting a Kickstarter to get parts into the hands of interested parties. Their offering all the base parts, without the electronics, for only $230. They claim the rest of the parts should be easy to find. Those who give more than $500 will get all the parts necessary to build the cheapest 3D printer on the market. if you're feeling even more generous, they'll build it for you for $885.
To prove the power of Eventorbot, the team has shared a video detailing a test print. It looks to be on par with other open source printers like the RepRap. The Eventorbot will continue to evolve as well due to its open source nature.
Open sourcing the 3D printer is proving to be the biggest step towards getting a 3D printer into the hands of everyone. Sooner than later, you'll start to see more and more people creating their own 3D printers. We might even start running into an issue where open source 3D printers start to cannibalize the sales of commercial 3D printers.[h/t: Make]