My Lego dam breach-loving sons would likely dig this thing (literally), especially in a drought:

The Verge writes,

[T]his special sandbox uses a Kinect sensor and a projector to create an interactive topographical map with real-time water simulations… You can use your hands or a shovel to push around the sand to form mounds and valleys, and the software uses the Kinect’s distance readings to overlay a color-coded topographic map atop the sand — red means high elevations and blue the opposite. If that weren’t enough there’s an accurate water simulator: open your hands above the sandbox and you’ll rain down water into the virtual world, which will then flow naturally and gather in the lowest-lying areas. 

Cue my typical invocation of Brave New World.

[YouTube]