Mine

        // modify the attributes for jsCalendar to our liking.
        foreach (array('start_date', 'end_date') as $element) {
          $form['event_fields'][$element]['#default_value'] = date('Y-m-d g:i a', strtotime($form['event_fields'][$element]['#default_value']));
          $form['event_fields'][$element]['#jscalendar_ifFormat'] = '%Y-%m-%d %l:%M %P';
          $form['event_fields'][$element]['#jscalendar_timeFormat'] = 12;
          $form['event_fields'][$element]['#description'] = NULL;
        }