Evolution of the Async Controller in ASP.NET MVC

Asynchronous operations in ASP.NET MVC have always been left a bit behind. They appeared in ASP.NET MVC 2, remained untouched in v3, but now in MVC 4 (especially in combination with C# 5 and async/await) they reached the same easiness of use of the standard synchronous controller. Check out that absolutely awesome stuff you can do with them now!