Which open-source ASP.Net projects are worth looking at for learning efforts?

Question

I'm trying to create (with your help) a list of open-source asp.net projects that are worth looking at, for reasons like a nice project design, nice solutions for common problems et cetera. The main effort of this list should be, that you feel that you have learned something from viewing a project's source code.

If you do post a project, please provide a link to the project page and tell us, why the project is worthy being metioned here. You can use this template:

Template:
Project Name:
URL:
Project Description:
Technologies used:
Why is the project worth looking at?:

List of recommendable open-source projects:

• Nerddinner

I'm making this a community wiki, so nobody should complain about this question. Feel free to edit it.

Answer 1

Make use of www.asp.net and aspallaince.com

Answer 2

• Project Name: NerdDinner.com - Where Geeks Eat
• URL: http://nerddinner.codeplex.com/
• Project Description: Organizing the world's nerds and helping them eat in packs.
• Technologies used:
  • ASP.NET MVC
  • OpenID
  • Virtual Earth
  • Twitter integration
  • iCal events
  • RSS Feeds
• Why is the project worth looking at?: The best way to learn a new framework is to build something with it. This tutorial walks through how to build a small, but complete, application using ASP.NET MVC, and introduces some of the core concepts behind it.