Sandbox
The sandbox is an obvious and useful tool for socializing young children, teaching them cooperation and allowing them wide latitude to invent and pretend and imagine, but it isn't obvious that it presents a useful learning tool to the brooding and jaded 2-12th grader. In the 70s we saw corporate experimentation with sandboxes in the boardroom or office, but they have given way to ping pong tables and pool tables and virtual outlets. Yet, the fluidity of the sandbox, as it allows groups and individuals to form and reform to pursue projects and flights of imagination suggests an interesting and useful dynamic. A classroom working on different aspects of a problem, with students circulating freely as they detect initiatives of interest might optimize individual participation and minimize marginal bench warming. It is an awfully speculative proposition, but here's an image of interest:
