Super Countdown Tracker.
Add the dates/times of important events in the near or distant future, and Super Countdown Tracker will tell you how much time is left.
My first "real" iOS app, Super Countdown Tracker began life as a Lambda School build week project, and I liked it so much I decided to polish it up and put it on the app store. It's a simple, lightweight app that does one thing very well—it tells you how much time is left until the events you feed it.