Notice: Caliburn.Micro is no longer actively developed or maintained and will be removed as an option in a future version of Windows Template Studio.
Caliburn.Micro is a popular, 3rd party framework based on the Model-View-ViewModel pattern. The framework helps you to separate your View from your Model which creates applications that are cleaner and easier to maintain and extend. It also creates testable applications and allows you to have a much thinner user interface layer (which is more difficult to test automatically).
You can find more out at Caliburn.Micro's homepage