Wrote and launched http://app.net/emptyinbox with my wife as a spare time project over the course of a few months. It's an inbox zero assistant for Gmail on iPhone. I am my own app's biggest fan, I use it almost daily and love it to death. :)

Unfortunately a crash bug was in the first version for people running the iphone app on an ipad, which wasn't discovered until after an AppAdvice review came out which drove tons of downloads...so that led to a bunch of 1-star reviews. But reviews since the fixed version have been very positive.