As I work to absorb the raft of recent announcements (mostly around MIX07), I discovered the
DLR - or dynamic language runtime.  Jim's blog is devoted to helping you to understand how to work with DLR languages, such as IronPython.  His entire blog is a great read!

Specifically from MIX is this:

"We're initially building four languages on top of the DLR - Python, JavaScript (EcmaScript 3.0), Visual Basic and Ruby. We shipped today both Python and JavaScript as part of the
Silverlight 1.1alpha1 release today. John Lam and I will be demoing all four languages, including VB and Ruby, working together during our talk tomorrow at 11:45."

Link to Jim Hugunin's Thinking Dynamic : Dynamic Languages and the Common Language Runtime (CLR)