Comment Enkin (Score 1) 110
Back when Google was running the first round of the Android programming challenge, a lot of excitement was generated by an augmented reality app called Enkin. To everybody's surprise, it didn't make it into the first round of finals, and seemd to disappear from sight. Turns out that Google had some other plans for them.
I did see one AR app in action on a G1, but I don't remember what it was called. The results were so-so... Hit and miss, sometimes it would get the buildings right, sometimes it wouldn't. But AR is definitely a very appealing possibility, and it'll probably improve very quickly. All the basic bits seem to be there.