Def Gallery - A web picture gallery application with support picture uploading, re-ordering, commenting, and deleting. It has a slide show view, a thumbnail view and a zoom view. [Open source, GPL] - http://dotnetnuke.adefwebserver.com/
OmniPortal - Built on the idea of having a web-portal-kernel, that could handle security, themeing, and localization. This means that any web based system on top of OmniPortal (i.e. ERP, CMS, CRM) can be created easily. Mono and .Net is supported. - http://omniportal.net/
ndCMS (Nickel and Dime Content Management System) - A .Net CMS featuring a wysiwyg editor, file manager, multi level roles and built-in http compression. [Open source, GPL] - http://ndcms-net.sourceforge.net
IT Hit MCMS Web Author Enhancement - Significantly changes the look and fill of MCMS Web Author making it more easy to manage site structure and resources. - http://mcms.ithit.com
Rainbow Portal - Initiative to build a comprehensive content management system using Microsoft's ASP.NET and C# technology. A VB version is also available. - http://www.rainbowportal.net
Intellyweb - Template-based web publishing tool. Developed with .NET. Certified as "Designed for Windows XP." - http://www.intellyweb.com/
Dozing Dogs - ASP.NET Content Management System with articles, news, events and blogs publishing support. - http://www.dozingdogs.com
CliqueSite - Content management software for ASP.NET running on IIS Web servers. Dynamically generates navigation and content through browser-based forms. - http://www.cliquesite.com/
ADXStudio - Offers an integrated web development framework suitable for building highly dynamic and personalized Internet, Extranet and Intranet web sites requiring content management within an IIS, Active Directory, and SQL environment. - http://www.adxstudio.com/