DotNetNuke, the open source web content management solution built on Microsoft's (NASDAQ: MSFT) .NET platform, introduced a new enterprise version this week. The biggest edition to the Enterprise version, which joins the Professional and Community editions, is a new content staging server, which provides a place to edit and approve content before publishing it to your website.
From Wikipedia:
The open source version of DotNetNuke is called the Community Edition and is available for free download on CodePlex. The Community Edition includes access to the source code of the framework and basic modules, and an MIT license [3] allowing flexible modification and distribution rights. The Community Edition is a popular web content management (WCM) system and application development framework for ASP.NET, with over 6,000,000 downloads and 600,000 production web sites as of June 2010.