nScriptHost is primarily intended to be easy to use and to try to hide the different requirements of the VBScript engine and the JScript engine.
The most recent documentation for nScriptHost is available on the wiki.
nScriptHost is very easy to use, however. Below is a minimalist example of how to use nScriptHost:string scriptText = "import System.Windows.Forms;\r\nMessageBox.Show(\"Hello World!\")";
As can be seen, using the engine can be incredibly simple. Despite the ease of use, the engine, scripting can provide a great deal of extended functionality for an application with very little work for the developer.
You can download nScriptHost here.
The Sourceforge Project page for nScriptHost is here.