John Papa decided to analyse the project for the HTML Hosting & Puzzle application for those who are interested in how it works.
The HTML Hosting & Puzzle application shows off using the new Silverlight 4 WebBrowser control in an out of browser application (note: you must run the application out of the browser for it to work). It allows you to use the control both interactively (meaning you can click the HTML within it and run it like an application). It also allows you to use the hosted HTML as a brush that you can apply to other Silverlight controls.