A UK startup called Light Blue Optics has announced they are developing a pocket-size digital projector, using breakthrough holographic techniques that allow using just a few small components, compared to the relatively bulky LCD projectors, which are still too big to carry around conveniently and still too expensive.
The long promised technology revolution in K12 classrooms has never delivered for a variety of reasons, but chief among them is that virtually no teachers have an LCD projector. It's pretty tough to use the Internet to change the way you teach if you can't project what it is you are teaching on the wall so students can see it. Small, inexpensive projectors would have large and mostly unanticipated impacts.