Free! THINKING WORLDS is a drag-and-drop 3D scene builder and visual programming editor that allows non-coders to build immersive gaming experiences and simulations. It appears more suited for creating virtual training exercises in large organizations, but with a free developer license it should provide a sufficient challenge for the ultra-techie educator. Beware. This is more of a summer project than weekend quick pick -- just imagine the learning curve if there were Scratch controls for every movement in Sim City. But if you're up to the task, there's still time to join this recently started MOOC on gameification. After all, a tool is only as good as the outcomes it makes possible.
"Tynker is a new computing platform designed specifically to teach children computational learning and programming skills in a fun and imaginative way. Tynker is inspired by Scratch from MIT. It is a completely browser-based implementation written using Open Web standards such as Javascript, HTML5, CSS3 and does not use Flash."
This is a fee based resource created by a Texas computer science teacher. It includes an entire computer science curriculum, and is aligned to the AP Computer Science exam.