You can draw circuit boards onto paper with this pen
 

When dreaming up that world-changing invention, wouldn't it be great if you could just sketch out the circuits and have them magically work? That's the idea behind Circuit Scribe, a ballpoint pen that's full of quick-drying ink that'll help you doodle your circuits on notebook paper. Emerging out of research from the University of Illinois, the team is now accepting your cash through Kickstarter to help bring it into the real world. $20 will get you a pen and an LED component, while $30 will buy you a basic kit, complete with plenty of accessories to help you test the systems to their fullest. We imagine it'll be a big hit with STEM educators as well as hobbyists, but if you're not yet convinced, check out the video to watch it in action.

http://www.engadget.com/2013/11/21/c...&ncid=rss_semi