ASP.NET MVC: Using Custom ViewModels with POST action methods

One of the top good practices for ASP.NET MVC is not to use the ViewData Dictionary, but to put your data in a strongly typed ViewModel instead. Many people seem to be using Linq to SQL entities as a ViewModel, because it’s a very comfortable approach. But what do you do if your view should contain data that is not included in any of your linq entities? This posting describes how to use custom shaped ViewModel classes for these cases.