Here is an interesting thing - C#.NET 4 came with and interesting concept of Covariance and Contravariance. These concepts relate to inheritance with generic types. The .NET 4 version also came with 'Parallel Programming' TPL library that allows us to do multi-threading in a convenient and efficient way. Other interesting things that came were Code Contracts, DLR, Lazy Initialization.
Hoven has been working on DOTNET training programs so that DOTNET can be made more interesting and easier to grasp. We follow full coding and full-designer, both approaches for ASP.NET.