The Rainbow project is an open source initiative to build a comprehensive content management system using Microsoft's ASP.NET and C# technologies.
Rainbow, available today in 29 languages, allows content authoring to be safely delegated to role-based team members who need little or no knowlege of HTML. Rainbow optionally supports a two-step approval-publish process. 75 plug-in modules are now included in the standard release, including support for an e-store, XML news feeds, Flash, Maps, Newsletter, Surveys, Forums, Document Management, Custom Lists, and more. It's also fairly easy to build your own custom modules using the guidelines provided on the Developer Documentation page.
Rainbow has received more than 156,000 downloads to date and more downloads of the new ASP.NET 2 version are occuring from the new SVN. Rainbow is already in production at many commercial internet and intranet sites.