This is a splash screen from a recent internal build of Office 2010, previously known as Office 14 posted by Zack from iGeneration. Nothing more to know about this build though.
There are news that Semblio might or might not be a part of Office 14, which is aimed at students. What is Semblio? According to Zack:
The Semblio application will allow you to create and add rich content and objects, such as human-interaction applets which are all available in the existing Semblio SDK. As everything is created in the WPF (Windows Presentation Foundation) format, it utilises the vector graphic scheme; enabling all images and text to be scalable with loss-less compression. You would be able to aggregate rich content from a variety of sources, from Word and Office content, PDF’s, and other third-party content such as Flash, YouTube, and Silverlight – naturally. When saving and viewing, it’ll wrap it up in a single filetype and will be viewable in the Semblio Player; a standalone application which views Semblio filetype, a little similar to Word Viewer, PowerPoint Viewer, or even Adobe Acrobat.