While it may lack some of the glamor and showmanship of the Miley Cyrus unicorn or the Yankee Stadium made out of toothpicks, the Stereolithography Machine is one of the most practically useful innovations at the fair.
The quality is so vastly superior to makerbots, and even to industry 3D printers. It uses a process building from top down, revealing a layer from the bath and curing it with UV light as it builds.
Not only is the resolution great, the plastic can be transparent, and the machine is under $3000!