IronRubyConsole.cs

using System;
using System.IO;
using System.Reflection;

using IronRuby;
using Microsoft.Scripting.Hosting;

namespace IronRubyConsole
{
    class Program
    {
        static void Main(string[] args)
        {
            var runtime = ScriptRuntime.CreateFromConfiguration();
            runtime.LoadAssembly(Assembly.LoadFrom("HtmlAgilityPack.dll"));
            
            var engine = Ruby.GetEngine(runtime);
            var context = Ruby.GetExecutionContext(engine);
            var scope = engine.CreateScope();

            scope.SetVariable("output", Console.Out);

            string filepath = Path.Combine(Environment.CurrentDirectory, "app.rb");

            engine.ExecuteFile(filepath, scope);

            Console.ReadLine();
        }
    }
}