gistfile1.cs

        protected void Application_Error(object sender, EventArgs e)
        {
            var exception = Server.GetLastError();
            Server.ClearError();

            var routeData = new RouteData();
            routeData.Values.Add("controller", "Error");
            routeData.Values.Add("action", "Index");

            Sitecore.Diagnostics.Log.Error("Application_Error invoked", exception, this);

            routeData.Values.Add("statusCode",
                                 exception.GetType() == typeof (HttpException)
                                     ? ((HttpException) exception).GetHttpCode()
                                     : 500);

            IController controller = new ErrorController();
            controller.Execute(new RequestContext(new HttpContextWrapper(Context), routeData));
        }