I'm not much of an astronomy geek, but I do work all night long, and am always looking for things to make the night go by faster. if you go to Heavens-Above Home Page, you can input your co-ordinates and it'll spit out neat things you can see, like satellites passing overhead.
An app that I could turn on while at work and bored, that would monitor my GPS location and provide alerts a few minutes before something worth seeing becomes visible, would be really cool. Also, if it provided star charts and the like, based on my location, that's something i would use, too.
Any astronomy buffs out there have any thoughts on this?