gistfile1.aw

<?php
/*
 * Implements hook_block_view().
 *
 * Displays an ad block.
 */
function mymodule_block_view($delta = '') {
  $block = array();

  switch ($delta) {
    case 'ad':
      $block['subject'] = t('This is an Ad');
      $block['content'] = t('Buy My Module!'),
      break;
  return $block;
}
?>