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