I have already written some proof of concept application that can be extended using PowerShell scripting, and also using IronPython at the same time. Embedding PowerShell requires no more than dozen additional lines in your app, same for IronPython.

Of course if you want to share some meaningful application state/features then you need to write proper classes and surrounding logic, but I found it to be very intuitive and easy (and I don't make living with everyday programming).

Just remember that classes, properties and methods you want to be available in scripts must be public. I've lost couple of hours until I found this.