gmail_add_date_label.user.js

// ==UserScript==
// @name           gmail_add_date_label.user.js
// @namespace      http://d.hatena.ne.jp/samurai20000/
// @include        http://mail.google.com/mail/#settings/labels
// ==/UserScript==

(function() {
     // main
     var schedule = one_year_calender();
     for (i = 0; i < schedule.length; i++) {
         label = schedule[i].getFullYear() + "." + (schedule[i].getMonth() + 1) + "." + schedule[i].getDate();
         
     }

     // utility
     function one_year_calender() {
         var today = new Date().getTime();
         var calender = [];
         for (i = 1; i < 365; i++) {
             add_time = i * 24 * 60 * 60 * 1000;
             var new_date = new Date(today + add_time);
             calender.push(new_date);
         }
         return calender;
     };

 })();