The concept behind my app was very specialist and highly personal to me, as the only audience for it would be my teenaged peer group. It's primary purpose is a geolocation-based, if the user enters any of 9 defined zones an information page pops up on the app detailing past events and memories associated with that place, serving as a pleasant nostalgia provider.

We used AppFurnace to build our applications: http://appfurnace.com/

There were several other features to the first draft, such as two pages dedicated to memorable quotes by members of the group, and a unique page for each user, to further the already established feeling of uniquity and involvement. Each personal page is linked to by an image which changes when clicked to increase the overall visual engagement of the final product, and each button is affiliated with the person's nickname, in accordance with the personal theme of the app.