Squiz has released its MySource Mini CMS under the GPL open source license, available as a VMware image from http://mini.squiz.net.

The Viper editing interface allows every element of a website to be edited in line and without a traditional 'backend' user interface. Viper offers true inline WYSIWYG “click-to-edit” functionality to easily create and manage content without technical skills or specialised training.

The free VMware image can be upgraded via a subscription to use Squiz's up-to-date service. This service keeps the entire platform updated without the need for human intervention.
About Squiz

Squiz is an Australian owned private company and the author of MySource Matrix, a fully supported enterprise class open source content management system used by over 600 organisations globally across government and industry.