Composite C1 Web Content Management System - .NET based, open source and a bundle of joy!
This project has moved from https://compositec1.codeplex.com/ (September 29th 2015). You can still use the forums and downloads a CodePlex, but we encourage you submit issues here.
Visit http://docs.composite.net/Getting-started/Guide
Download binaries from https://compositec1.codeplex.com/releases/
Head over to https://compositec1.codeplex.com/discussions to ask questions
Composite is the company driving the development of Composite C1. We are working full time on this CMS and on other cool stuff you can add to it. We are situated in Copenhagen and Kiev.
We are owned by Orckestra, a Montreal based company specializing in enterprise commerce software. They actively take part in the development as well.
You can visit us at http://www.composite.net and http://www.orckestra.com/