Today we released the source code for the built-in ASP.NET 2.0 Membership, Role Management, Site Navigation, Session State, Profile, Web Events, and Web Part Personalization providers
This is a great thing - not only is Microsoft being much more helpful by providing sample code to let us develop (in this case) pluggable providers, but rather than releasing ????? code which just demonstrates the concepts, they're releasing the production code that we're already using.
The ASP.Net developer centre also great documentation on the Provider design pattern/model, and the individual provider types used by ASP.Net 2.0.
Finally, they've also released this under the Microsoft Permissive License (Ms-PL) - a license that allows and encourages the development of derivative works.
I for one can see myself using all of these types of providers at some point or other in my current project, so these samples are going to make my life much easier. Good stuff.