title: Generate a hour:minute select list
body: <p>Is there a way to generate something like the following markup:</p>
  
  <pre><code>&lt;select&gt; 
      &lt;option value="0000"&gt;00:00&lt;/option&gt;
      &lt;option value="0030"&gt;00:30&lt;/option&gt;
      &lt;option value="0100"&gt;01:00&lt;/option&gt;
      &lt;option value="0130"&gt;01:30&lt;/option&gt;
      &lt;option value="0200"&gt;02:00&lt;/option&gt;
      &lt;option value="0230"&gt;02:30&lt;/option&gt;
      &lt;option value="0300"&gt;03:00&lt;/option&gt;
      &lt;!--rest of options omitted for brevity--&gt;
  &lt;/select&gt;
  </code></pre>
  
  <p>... all the way up to 23:30 - so repeating every 30 minutes?</p>
  
  <p>I'm using rails 3, and while this works, it doesn't include the minutes (in my case, every half hour)  </p>
  
  <pre><code>select_hour(13, :prompt =&gt; 'Choose hour')
  </code></pre>