I wonder if learning different programming languages does the same? Or as the comment earlier states, is it just a matter of challenging yourself and learning new things that does the same?
People ask me all the time "how much do you think it would cost to build <insert app idea>?". Now I just point them to this site. Kind of like let me google the for you but for app ides. I do realize it's free advertising for the Crew which is a dev group but still pretty cool and it's free.
I love this app because it's simple and lets me just get train arrivals for my favorite stops. I don't have to tell it where I'm going or anything. I've used the NYC subway system my whole life I don't need a routing app and I find them annoying.