Some scientists at University of Illinois have developed a pen that essentially draws circuit diagrams that will actually work, but no, you can't use it to draw a hamburger that you can actually eat because this is science, not magic, unfortunately. The pen uses a silver solution (the element, not the color) that allows the wielder to draw working electronic circuits on a number of different surfaces.
Printers have used metallic ink to print circuits for a while now, but this pen, while being cheaper and more versatile, also adds a little bit of unique, artistic flair to the process. This, combined with the fact that the ink will maintain connectivity even after being folded, could make some waves in the worlds of disposable electronics and electronic art. Sure, this thing probably isn't going to change the whole world, but the parts of it that it does change should be pretty awesome.
(via Short Sharp Science)