Found this site really interesting from Maxim V. Karpov, basically it's a blog with a focus on the use of design patterns in .NET - which I personally think are currently not widely underused but could provide a huge boost to a whole lot of developers. Maxim recently wrote an article looking at the ASP.NET Out Of Process Session State - which is in itself an implementation of the Intercepting Filter pattern. If you're interested in patterns in .NET you could do a lot worse than look at the Microsoft Patterns site - whilst it isn't perfect (I'd personally like to see a WHOLE lot more example code) it is a great introduction.