We recently finished a big refactoring of the BigBlueButton client using PureMVC framework, a very clean implementation of the Model-Viewer-Controller design pattern.
We chose PureMVC over Cairngorm because it was less verbose and its design facilitated smaller partitions of code (read: easier for others to understand).
Right now, we're working on making BigBlueButton modular, and we've been adapting the Multicore capabilities of PureMVC to enable dynamic loading and unloading of client modules. Looks like others are picking up on our efforts.
