The Greenbush Southeast Kansas Educational Service Center is developing what I'd call a distribution of Croquet called Edusim. It is packaged for (newer) Mac's, and they've particularly been focused on using a smartboard to interact with the virtual world. Check out the videos, and if you've got a G5 or later Mac download it and try it out (the modifications to make this work on Linux and Windows would be minor; unmodified, it starts up but doesn't quite load the 3-d environment on my Ubuntu laptop).
One little feature I noticed in the video that I wasn't aware of in my previous experiments with Croquet is dragging and dropping images directly from your desktop into the Croquet world. Very nice. That's the kind of "intuitive" feature I assume wouldn't work.
I'm particularly excited that this work is taking place at an "Educational Service Center." These organizations are well positioned to pioneer open source development and implementation in US K-12 schools and should be an important vector in the future. And yes, they do have a proposal in to the Digital Media and Learning Competition.