Caliburn.Micro is an MVVM framework that aims to simplify building WPF, Silverlight, and Windows Phone applications using common UI patterns like MVVM. It provides features like automatic view-viewmodel resolution through conventions, an event aggregator for loose coupling between components, window management, and coroutines for asynchronous programming. The framework handles common tasks like UI lifecycle management and removes much of the boilerplate code associated with building MVVM applications.