title: ruby DateTime parsing from 'mm/dd/yyyy' format
body: <p>I am using <code>ruby 1.9.3</code> and want to get <code>Date or Time</code> object from '<code>mm/dd/yyyy</code>' date <code>format</code> string</p>
  
  <pre><code>Time.zone.parse("12/22/2011")
  </code></pre>
  
  <p>this is giving me <code>*** ArgumentError Exception: argument out of range</code></p>