I had been thinking that augmented reality was a ways off, requiring funny goggles, crazy retinal projectors, holograms, or whatever. Then I saw that all you really need is an iPhone with a video camera in the back. e.g.:
Augmented reality is The Next Big Thing, in the sense that twenty years from now we'll look back and say, "Do you remember when we didn't have that?" Experiencing its development in real time, it is a lot more fragmentary, a lot of separate technologies that are suddenly coalescing into a new gestalt.