Silverlight Showcase Launcher is a simple & efficient way to display a showcase.
It was made for the TechEd Europe 2010 Silverlight Booth & you can try it out here: http://www.brainsiders.com//TEE2010/SLShowcase/default.html
It uses some code from the Bouncing Plane Demo (from Henry Han see: http://blogs.msdn.com/b/henryh/archive/2009/03/20/mix09-the-gratuitous-graphics-demo.aspx )
For the Horizontal Carousel I’ve used the Flow Layouts Library, see http://slflow.codeplex.com/, from Simon Ferquel.
Also, for the circular animation I have used the smart technique conceived by John Bruin - http://www.johnbruin.net/index.php/category/silverlight/ - Thanks John!