A solver for the pencil and paper vector game "Racetrack":
http://en.wikipedia.org/wiki/Racetrack_%28game%29
I wrote this in high school (2011/2012) before I knew about BFS/DFS or even stacks/queues, so I actually ended up implementing some of these things without knowing it at the time.
I thought it would be interesting to model this pencil and paper game in Java, as it seemed to have some interesting vector math that would be necessary to solve it. The program uses a fairly inefficient depth first search to find the paths that take the least amount of turns to complete. A detailed synopsis of various tactics used in solving this game is detailed in RacetrackSolver.pptx in the repository for now.