My favorite non game mobile app has to be "Silent Film Director" for the iPhone and various other iProducts. Essentially you can make old timey looking videos that look all grainy and old and silent filmlike. It has silent film music (1920's piano) and dialog cards that can be inserted. My friends have it and have made some really fun videos with it. It is the one app I have finally found that I would be willing to pay for. I believe it has more features than I mentioned, but I haven't had much of a chance to mess around and experiment with it yet on my own mobile device.