A sandbox game with real sand. Developers Monobanda explain: "Monobanda has created a sandbox game with real sand, in which up to four players at a time control a ball that can roll around, jump and glide through the Mimicry world. Tiny virtual characters roll around in the sandbox. You can build obstacles for them or create a racetrack." Yes, you play in your sandpit to create the game's environment.
This bizarre and extraordinarily clever augmented reality project has a video and a couple more images, which you can see below. (Via the almighty Indie Games.)