I'm keening on Windows Workflow Foundation. It's really a new kind of approach to the software implementation. It's totally extensible by the coder but at the beginning it's not easy because a classical Visual Studio user doesn't know where he can start and where he can arrive. Then you need a book or a tutorial about WF to understand the behind idea and what is the aim of this development  environment.

 

Then it will be clear that it is designed to project complex workflows and don't never lose the complete view of the project. WF application hasn't a User Interface, it could be a dll or at most a console application.

Then to build an application with this technology you probably need to implement a User Interface level also that provide and receive data from the WF dll.