One of the most exciting things about HoloLens is that no one is entirely sure what to do with it. It's a game-changing device that's bound to bring some revolutionary new applications. So far, developers have been getting the hang of it by adapting old ideas to interact with the real world. Now, some fine folks have put together a brilliant demo of the classic game Lemmings. But this time you have to save the title characters from falling off of your furniture.