title: How do you find a random open port in Ruby?
body: <p>If you call <code>DRb.start_service(nil, some_obj)</code> and then <code>DRb.uri</code>, you get back the local URI, including a port number, that another process can use to make calls.</p>
  
  <p>I'm looking to just have some code find a random available port and return that port number, instead of starting up a full-fledged <code>DRb</code> service. Is there a simple way to do this in Ruby?</p>