site.com/about
site.com/ru-ru/about
site.com/ru-ru/categories/category1/article/12
site.com/categories/category1/article/12

public abstract class ControllerBase : Controller
    {
        public BECulture CurrentCulture { get; set; }
        protected override void OnActionExecuting(ActionExecutingContext filterContext)
        {
            string culture = filterContext.RouteData.Values[MvcApplication.CultureParamerName] as string;
            CultureInfo cultureInfo;
            if (!string.IsNullOrWhiteSpace(culture))
            {
                cultureInfo = CultureInfo
                    .GetCultures(CultureTypes.AllCultures)
                    .FirstOrDefault(x => x.Name.ToLower() == culture);
                if (cultureInfo == null)
                    cultureInfo = Facade.Common.DefaultCulture;
                Thread.CurrentThread.CurrentCulture = cultureInfo;
                Thread.CurrentThread.CurrentUICulture = cultureInfo;
            }
            else
            {
                Thread.CurrentThread.CurrentCulture = Facade.Common.DefaultCulture;
                Thread.CurrentThread.CurrentUICulture = Facade.Common.DefaultCulture;
            }

            base.OnActionExecuting(filterContext);
        }

 routes.MapRoute(
               "HomeWithoutCulture_Route",
               "{action}",
               new { controller = "home", culture = "en-us" }
               );

            routes.MapRoute(
                "Home_Route",
                "{culture}/{action}",
                new { controller = "home", culture = "en-us" }
                );


            routes.MapRoute(
                "Default_Route",
                "{culture}/{controller}/{action}/{id}",
                new { controller = "home", action = "index", id = 1, culture = "en-us" },
                new { id = @"\d" }
                );

<li>@Html.ActionLink(Resources.Strings.About_Link, "about", "home")</li>