Prism for Windows 8 Apps
Prism 4.5 (for .Net FW 4.5) is due to be release next month. But the good news is the future release for windows 8 apps. With current code name Kona hat will provide guidance on developing line of business (LOB) apps for Windows 8, previously known as Prism for WinRT.
Prism is the most notable composite UI framework for WPF (and former Silverlight) LOB (line of business) applications. It provides an easy to use event aggregator pattern for loosely coupled controls in the application as well as composition of these control into a meaningful UI.