Just released are four new QuickApps, demo apps that you can use, study, and/or modify.  They take advantage of Windows Live and Microsoft tools such as Silverlight, Windows Live ID, Messenger, and more.  Angus Logan has more, including a description of the purposes of QuickApps:

The Quick Apps have 3 purposes

1. Examples of what is possible – use them, play with them, get ideas!
2. Technical reference – if you want to use a Live Platform API, there is a good chance it will be in a Quick App, check out the code to see how it was implemented.
3. Starting point – these end-to-end applications are licensed under a fairly liberal (OSI approved) license, you can use them as starting points for your own applications.

One of the new QuickApps, Retail, includes a Wall of Video, using Silverlight:

…kind of like the red shoes :).