This dll takes some of the pain away from registering routes in ASP.NET MVC (including having to alter your routes when you rename a controller !)
It's on Nuget as "Mvc.Routing"

So instead of registering routes like this :

	routes.MapRoute(
	    "foobar route",
	    "foo/{someParam}/bar",
	    new { controller = "Foo", action = "Bar" }
	);

You can just call :

	Routing.Register(typeof(MvcApplication).Assembly);

And then tag your controllers : 

public class FooController : Controller 
{
	[Get("foo/{someParam}/bar")]
	public ActionResult Bar(string someParam) {
		// whatever
	}
}

There are attributes for Get, Post, Put, Patch and Delete
The attributes behave like the normal HttpGet, HttpPost (etc) attributes - ie if you tag an action as Get(), then you can't post to it

You can use them in conjunction with the normal Http* attributes, for example :

public class FooController : Controller 
{
	[Get("foo/new")]
	public ActionResult New() {
		// whatever
	}

	[HttpPost]
	public ActionResult Create(Bar bar) {
		// whatever
	}
}

If you don't use the HttpGet / HttpPost attributes for your actions, you can still register routes like so :

public class FooController : Controller 
{
	[Route("foo/{id}")]
	public ActionResult View(Guid id) {
		// whatever
	}

	[Route("foos")]
	public ActionResult List() {
		// whatever
	}	
}

Testing your routes is also pretty simple, below is an example using Mspec (Machine.Specifications) :

    [Subject(typeof(TestController), "Given a test controller has marked the Index method as Get")]
    public class when_registering_routes : register_route_context
    {
        Establish context = () =>
        {
            theExpectedRouteUrl = "all/routes/are/mine";
            theExpectedActionName = "Index";
            theExpectedControllerName = "Test";
        };

        Because of = () =>
        {
            Routing.Register(typeof(TestController).Assembly);
            theRoute =
                RouteTable.Routes.Select(x => x as Route).Where(x => x.Url == theExpectedRouteUrl).FirstOrDefault();
        };

        Behaves_like<route_should_be_registered> route_should_be_registered;
    }

    See the project specs here for more examples : https://github.com/benjaminkeeping/Mvc.Routing/tree/master/src/Mvc.Routing.Specs/registration