Mike Taulty (which, by the way, has a great blog) wrote a short tutorial on how to figure out what the .NET Framework code does when you suddenly get an exception and you don’t really know why it is being thrown from the framework.

He also shows how to load our favorite WinDbg Extension – SOS – into Visual Studio and use it while debugging as well as use Reflector to disassemble the framework’s code into readable C# or VB.NET code.
I also briefly talked about loading SOS into Visual Studio a while back and mentioned the use of Reflector all over the place (because its such a great and useful utility!).

Mike, if you are reading this – Yes, I also do what you do and I suppose almost everyone who actually wants to know what is happening under the hood in the .NET framework 🙂