The idea that won state and ranked 11th-or-so for the national (really international) competition was, ultimately, the product of a week of "what are we going to do because our other project is garbage."
Initially we made a little gimmick called Planyr, an agenda program running entirely in Java that allows someone to assign one (1) event per day. It was useless and, probably worse than that, just painful to use. Regionally, out of two people, we finished second and therefore earned the honor of going to the State competition. We had two months to figure out the garbage sitting in front of us, and after a week of Computer Science III classes we put together our heads, combining our interests and put it behind a social cause—food deserts.
From that came our actual project, Cookyr, which had a bit more substance to it—it was a image-recognition-based food cataloger that allowed users to create accounts and build up a virtual fridge, stocked with ingredients and easy-lookup recipes.
To the left are two screenshots—one of the repo (you can find it at my Github) and one of the site as it would appear to the user "banksy."