Today, Microsoft announced the availability of ASP.NET MVC Framework 2.0. The ASP.NET Model-View-Controller (MVC) pattern will promote the creation of higher-quality software through greater componentization and testability in .NET Web apps. According to Microsoft new features in ASP.NET MVC 2 include:

• Client side validation: Automatic support for JavaScript validation in the Web browser. Developers can also extend it to use a client validation framework of their choice by simply writing an adapter which reads in the JSON metadata and calls into the client validation library.
• Enhanced model validation: Developers can use the DataAnnotation validation support built-into the Microsoft .NET Framework to declaratively define and add validation rules to business objects and properties.   
• Asynchronous controller: Support for asynchronous action methods that can be used to improve performance when dealing with long running operations.
• Support for areas including tooling:  Ability to organize ASP.NET MVC applications into multiple areas, each with its own models, views and controllers. Visual Studio tooling support is available to easily add new areas to applications.
• Auto-scaffold UI helpers with customizable templates: Helps to refactor common UI elements into reusable templates.