title: How to find max value of Item2 in Tuple<string, DateTime>
body: <p>Okay, I've done this before, but I'm drawing a blank, so I'm hoping the big brains here on SO can bail me out.</p>
  
  <p>I have a <code>Tuple&lt;string, DateTime&gt;</code> where the string is a FileName and the DateTime is the last date that file was sent by a process.  The FileNames will not be identical, but they all confirm to a filemask of some kind (for instance, I might have several entries where the <code>string</code> conforms to file mask <code>"????AD??"</code>).  I want to find the most recent <code>DateTime</code> for a given filemask.</p>
  
  <p>I can't remember how I resolved this problem before, and it was at a previous employer, so I can't even cannibalize my old code.  Any help would be greatly appreciated.</p>
  
  <p>Clarification (since this could be a little obtuse)</p>
  
  <p>Given:</p>
  
  <pre><code>(0501AD01, 5/2/2010)
  (0502AD02, 5/3/2010)
  (0503AD03, 5/4/2010)
  &lt;snip&gt;
  (0803AD99, 8/4/2010)
  (0804AD00, 8/5/2010)
  (0805AD01, 8/6/2010)
  </code></pre>
  
  <p>I want to return <code>8/6/2010</code></p>