The three initial concepts that I came up with for the iPhone apps were for the Hiking subculture, which was technically specifically for older hikers. There was a trail index, with an option to "image map" trails through users photos of the trail, and a lot of stuff that would help you choose trails in your local area, as well as ones that you might like when you are traveling elsewhere. The second idea was an app that would allow you to scan tags of new equipment that you got or want to get, and it will give you user opinions and ratings, and some other information about the product.
The final idea, and the one that I moved forward with was the health related app. As older hikers, while they might be fit, they still need to be more aware of themselves and maybe younger hikers might be. For this, they can imput any health concerns they have (meds and vitamins they take, physical issues or other problems that could be affected by the environment, ect) and the app will remind them when they need to drink water, take their rest breaks, maybe take their pills, and then also guide them toward trails that suit them best. This app also sends an email to a friend in their address book with their plans, so that if something were to happen to them, someone would know!
So, these are the wireframes that I tossed around. I got a lot of good feedback and a lot of help and advice, which I needed. Changes to come!