I am very excited with the ADL Sandbox project and Virtual World Framework at all, and that it is available in open source to experiment with.
By the way, I am from Smalltalk world and an acceptor of OpenCroquet architecture, which has it's own history. OpenCroquet in it's latest form of OpenQwaq take all the features and benefits from the platform being realized on (the open source Smalltalk language dialect Squeak).
But, Virtual World Framework goes further now, especially in moving from class based language architecture to prototypes, that gives a shared code and behaviours used in distributed computation, to be modified at runtime!
So, that's one of the main criteria, I am start moving now from OpenCroquet to Virtual World Framework, despite of sadness of parting with all the benefits of Smalltalk language and it's IDE, comparable to JavaScript and Ruby. Although, I have the insights of looking a Smalltalk language as a DSL language for Virtual World Framework in the future (for example as Seaside web framework for HTML and JavaScript).
ADL Sandbox project uses already one JavaScript language for all stuff. And one interesting thing to realize in it is having OMeta'JS workspace inside Sandbox script editor, which will allow to define own language's grammar and replicate it through the application instances, then have a running scripts on that shared grammar. Almost all JavaScript language dynamic capabilities will be used in distributed computation then. For example, you could have all the languages down from Logo (Turtle graphics) to Smalltalk available for scripting the virtual world just in the Web browser.
More over the integration between LivelyKernel and Virtual World Framework will give the endless capabilities of in browser project development and editing.
So, I have started using the ADL Sandbox project and Virtual World Framework to build a Virtual Learning Environment for modern mathematics and phisics, exploring the new ways of developing the concrete tools for modelling, rendering and interaction with the content of the virtual world.
Will post about the progress here.