I wrote before about how Patterns and Practices is taking the lessons of CAB and applying them to a new project - the development of a compositional application architecture for WPF. The project is called Prism.
Prism is catching the first rays of public sunshine. Glenn Block announced the a Prism drop in his blog post today. It comes with a reference implementation (RI) to motivate the design decisions and demonstrate Prism at work.
I'm looking forward to digging in. I've seen some earlier Prism facets and been pleased with the direction.
I'll repeat Glenn's caveats: these are not real Prism bits - not beta, not CTP. They are more like spikes. Assume almost everything will change. Don't even dream of using it in production.
On the other hand, I think it's well worth examining to see where Prism is headed and to confirm for yourself that "by gosh, they might actually deliver something useful and intelligible in reasonable time." They've made no delivery promises - not about content, not about timing. But the auguries are very good.