What are the options? This is what I found so far:
* Dynamically compile C# or VB.NET code into an assembly and execute it – I used this route before
* Implement Windows Scripting Host interfaces. Found a couple of links (see below), but no full implementation
* Use DLR
* Use a number of “Script.NET” like projects

Scripting using WSH:
CodeProject: C# interface defintions
DDJ article series on building Active Scripting Host in C#
In particular, part four seems to be of interest.

Unfortunately, there is no ready-to-use download, and it seems like a lot of work. Yes, I am a lazy guy and I have a tight deadline 🙂

UPD: found 8 year old VB.NET scripting sample ScriptPad from MSDN