DotVVM
Open source MVVM framework for Web Apps
... smaller than other ASP.NET-based frameworks. DotVVM offers a free Visual Studio extension giving you all the comfort you are used to. DotVVM comes with ready-made components you can use in your HTML files. The state and user interactions are handled in view models - C# classes. The controls render simple HTML which can be styled easily. MVVM pattern and data-binding expressions are used to access the UI components.