random-date.js

var randomDate = function() {
  var now = new Date(),
      minMonth = 1, maxMonth = now.getMonth(),
      minDay = 1, maxDay = 26,
      randMonth, randDay, date;

  randMonth = Math.floor(Math.random() * (maxMonth - minMonth + 1) + minMonth);
  randDay = Math.floor(Math.random() * (maxDay - minDay + 1) + minDay);

  date = new Date(2013, randMonth, randDay);
  return (date.getDate() > 9 ? '' : '0') + date.getDate() + '.' + (date.getMonth() > 9 ? '' : '0') + date.getMonth() + '.' + date.getFullYear();
}