The researchers at MIT have developed a technology in which it's possible to build transparent displays with silver nanoparticles! According to the researchers, it's fairly cheap to develop such displays and it's an important technology that will provide new possibilties in many projects. The little prototype they used costed only 10 dollars in total, which is very cheap. MIT believes that it could find its application in google glasses; windows from cars, from shops or just from your house, and even on whole walls from skyscrapers. It would offer better viewing angles and resolutions than the conventional projection techniques. Until now they only used the primary color blue, but with all 3 primary colors they should be able to display full color images or videos.
The video contains more information of this new technology: