I could use the box2d library for a video game. I have seen the classic use with the now build-in ofxKinect where you use your body to play with boxes. I would stray from this idea and I think I could create a interesting game using this library.
My mom purchased a LeapMotion right when they came out and used it a bit then gave it to me since she does the standard set of tasks on the computer and there wasn’t a compelling reason for her to use it. So I have had this LeapMotion for the past 6 months without any idea of how to use, so seems like a perfect chance to actually use it! Could be used as an interface to a video game.
I set up Spine in C# XNA, but then I never ended up making the game I had set it all up for but I loved the engine’s animation capabilities. Since I have had some experience with it, could go mega add-on and try making a video game that uses a LeapMotion as input, uses box2d for physics and uses Spine for animations.