You too can leverage the design surface technology in Visual Studio 2005 – you can see great examples of this today in the Beta with the Class Designer, Whitehorse designers (Logical Datacenter Diagrams, System Diagram, etc.).
So you can have a designer leveraging the rich design surface in VS2005 for any DSL you can imagine, enterprise patterns, business processes or even (and particularly useful in a huge number of cases) to create/modify XML files. Microsoft has a huge array of very complex XML files to drive our products, imagine a DSL describing this “language” and a designer to allow you to visualize and create these files without cracking notepad open J
I’m by no means an expert, but a newbie just scratching the surface….