The document discusses Dynamic Silverlight which adds support for Dynamic Language Runtime (DLR) languages to the Silverlight platform. This allows Silverlight applications to be coded using dynamic languages like Ruby and Python instead of just C#. The DLR provides a dynamic type system and allows different languages to run on the Common Language Runtime (CLR). A demo is shown of a very basic Silverlight application coded in Ruby that calls into a C# DLL, demonstrating interoperability between DLR and CLR languages.

1. Dynamic Silverlight and a bit of Ruby