Adding ASP.NET Tracing to IIS 7.0 Failed Request Tracing

IIS 7.0 Failed Request Tracing (for historical reasons internally we refer to it as FREB, since it used to be called Failed Request Event Buffering, and there are no "good-sounding-decent" acronyms for the new name) is probably the best diagnosing tool that IIS has ever had (that doesn't require Debugging skills), in a simplistic way it exposes all the interesting events that happen during the request processing in a way that allows you to really understand what went wrong with any request.