function _optotrip_block_flickr() {
  $termtext = _optotrip_get_block_context();
  if ($termtext == '') {
    return NULL;
  }

  $starttime = microtime(TRUE);

  lightbox2_add_files();

  // perform search
  $args = array(
    'text' => $termtext,
    'per_page' => 16,
    'sort' => 'interestingness-desc', // 'relevance',
  );
 
  // if results found, emit block content
  if ($photos = flickr_photos_search('', 1, $args)) {
    $content = '<div class="myflickr">';
    foreach ($photos['photo'] as $photo) {
      $content .= theme('flickr_photo', $photo, 's', array('rel' => 'lightbox[flickr]') );
      // print theme('flickr_photo_box', $photo, 's');
    }
    $content .= '</div>';
    // HACK: add some padding to the flickr images
    drupal_set_html_head('<style type="text/css" media="all">div.myflickr img { padding: 5px; }</style>');
  }
  else {
    $content = t('No photos found');
  }

  // dsm("_optotrip_block_flickr($termtext) ===> ". (microtime(TRUE) - $starttime));

  // return the block information
  return array(
    'subject' => t('Flickr for: @name', array('@name' => $termtext)),
    'content' => $content,
  );
}