In grad school in a class on the Semantic Web, we created a very simple iOS flashcard game that used flags, animals, monuments, and a few other details to help kids remember details about countries. It was a good exercise to pull all of these bits together using Linked Data, although I am not sure how well it would have scaled.<p>I have a video of it somewhere ...<p>ETA: <a href="https://www.youtube.com/watch?v=vev_2MATqNQ" rel="nofollow">https://www.youtube.com/watch?v=vev_2MATqNQ</a>