1、Silverlight + OpenXML Video ：This is a Silverlight proof of concept application that displays random commercials on a video that are extracted from an Excel spreadsheet.
http://www.codeplex.com/openxmlvideo
2、Free Silverlight Chart Control  ：The FreeSilverlightChart Control provides charting solution in a silverlight environment. It uses XAML and C# to display charts on the silverlight platform.
http://www.codeplex.com/FreeSilverlightChart3、Silverlight +OpenXML Page Turn ：This is a Silverlight proof of concept application that takes a simple Word document and displays it in the form of a book. I used Silverlight PageTurn demo as a foundation
http://www.codeplex.com/openxmlpageturn
4、Clog: Client Logging ：A customizable log provider system that allows you to harness your existing logging system to log client side messages to your server using WCF or asmx Web Services. Includes Silverlight and WPF sample applications.
http://www.codeplex.com/Clog
5、Silverlight Streaming Library ：Provides easy programmatic access to Silverlight Streaming accounts to upload, delete and browse silverlight applications, files, etc
http://www.codeplex.com/slsl
6、AgTweener：agTweener is a c# Silverlight library based on the Tweener Actionscript library for Flash/Flex. A preset list of transition functions based on Robert Penner's easing equations is available
http://www.codeplex.com/agTweener
7、DLRScript is a SilverLight 2.0 sample using the DLR. It lets you use DLR-based languages in the Script tag of a normal HTML (or .aspx, or .jsp or .php, etc.) page.
http://www.codeplex.com/DLRScript8、 Webyog公司刚发布了一套非常酷的开源Silverlight图表控件（带有动画支持），允许你轻松地建造好看的图表，他们的模型极大地方便了在现有的HTML或AJAX应用中图表组件的使用。
http://www.visifire.com/index.php9、Silverlight™ Dynamic Languages SDK http://www.codeplex.com/sdlsdk10、Dynamic Geometry
http://www.codeplex.com/DynamicGeometry11、Silverlight Photo Album
http://www.codeplex.com/photoalbum12、Silverlight String-To-PathGeometry Converter
http://www.codeplex.com/StringToPathGeometry13、M.O.M
http://www.codeplex.com/mom
14、Silverlight P2P library
http://www.codeplex.com/SilverlightP2P15、Bloom is a light weight IoC framework for Silverlight 2 and the .net Framework CLR with optional Logging and Serialization application blocks.
http://www.codeplex.com/Bloom
16、Silverlight Code Camp Starter template is designed to provide a simple solution to quickly raising a Code Camp web site using Silverlight. The initial goal for the template was to decrease complexity and server requirements.
http://www.codeplex.com/silverlightcodecamp
17 、silverstone ：A Lightweight MVC Framework for Silverlight
http://code.google.com/p/silverstone/

18、SilverlightDesktop.net SilverlightDesktop.net is a Open-Source ASP.NET framework that allows you to dynamically load Silverlight modules into resizable draggable windows.

http://www.codeproject.com/KB/aspnet/SilverlightDesktop.aspx

19、The Free Silverlight Multi File Uploader is a free Silverlight 2 application. It can be used to upload multiple files simultaneously to your website.
http://www.codeplex.com/SLFileUpload

20、Visifire is a set of open source data visualization components - powered by Microsoft Silverlight and WPF. With Visifire you can create and embed visually stunning animated Charts within minutes. Visifire is easy to use and independent of the server side technology.

http://www.codeplex.com/visifire

21、WPF/Silverlight enhancements that enable the use of standard HierarchicalDataTemplates and DataTemplates to display complex data hierarchies that contain multiple ItemsSources. DataTemplate search criteria is expanded to support find by item interface, and/or base type.
Complex Hierarchical Data Templates

Silverlight DOM Integration Sample

http://code.msdn.microsoft.com/SilverlightDOM