My friend Nick and I came up with an idea for making a tool for ecosystem education. Similar to other hierarchical systems, ecosystems also tend to have a distinct "layered" distribution of flora and fauna (e.g. the type of creatures one would encounter in an ocean at different levels of depth varies greatly). To that end, we designed and built a tangible ecosystem browser called Waferlens.
Using connected components on a Kinect depth stream to track a sheet of thick paper, we augmented it with depth arranged content (using an overhead projector) that included images and descriptions of the various organisms making up an ecosystem.
Here's a video demo of this system in action: