title: Pandas plot doesn't show
body: <p>When using this in a script (not IPython), nothing happens, i.e. the plot window doesn't appear :</p>
  
  <pre><code>import numpy as np
  import pandas as pd
  ts = pd.Series(np.random.randn(1000), index=pd.date_range('1/1/2000', periods=1000))
  ts.plot()
  </code></pre>
  
  <p>Even when adding <code>time.sleep(5)</code>, there is still nothing. Why?</p>
  
  <p>Is there a way to do it, <strong>without having to manually call matplotlib</strong> ?</p>