JurassicTools provides additions to the Jurassic JS engine.

Some features include:

• Works cross-platform (tested with .NET 4.0 and Mono 2.10)
• Easily expose classes without the need to inherit from FunctionInstance or similar
• That means you can use your code either from JS or from .NET
• Support for enums, varargs and automatic conversion of compatible types
• Transparent objects
• Delegates
• Expose 3rd party classes (even .NET framework stuff)
• Tight control over what gets exposed and what not

Check this page and this post for more information and examples!