Indexer.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;

namespace IndexerTest
{
    class Program
    {
        static void Main(string[] args)
        {
            var test = new MyModule();

            foreach (var route in test.Routes)
            {
                route.Action("moo!");
            }
        }
    }

    public class MyModule : NancyModule
    {
        public MyModule()
        {
            Get["Test"] = s => Console.WriteLine("Get: " + s);

            Put["Test"] = s => Console.WriteLine("Put: " + s);
        }
    }

    public abstract class NancyModule
    {
        private List<Route> routes; 
        public IEnumerable<Route> Routes
        {
            get
            {
                return this.routes;
            }
        }

        public NancyModule()
        {
            this.routes = new List<Route>();
        }

        public RouteIndexer Get
        {
            get
            {
                return new RouteIndexer("Get", this);
            }
        }

        public RouteIndexer Put
        {
            get
            {
                return new RouteIndexer("Put", this);
            }
        }

        public class RouteIndexer
        {
            private string method;

            private NancyModule parentModule;

            public RouteIndexer(string method, NancyModule parentModule)
            {
                this.method = method;
                this.parentModule = parentModule;
            }

            public Action<string> this[string data]
            {
                set
                {
                    this.parentModule.routes.Add(new Route() { Method = this.method, Data = data, Action = value });
                }
            }
        }
    }

    public class Route
    {
        public string Method { get; set; }

        public string Data { get; set; }

        public Action<string> Action { get; set; }
    }
}