The example script for dynamic functions in the updated super-cache (1.4)

dynamic.php

<?php
/* NEW DYNAMIC FUNCTION */
define( 'OAM_DYNAMIC_YOUR_FUNCTION', 'CACHE_OAM_YOUR_TAG');

function OAM_your_function_filter( &$cachedata = 0) {
  if (defined('OAM_DYNAMIC_YOUR_FUNCTION_TEXT'))
    return str_replace( OAM_DYNAMIC_YOUR_FUNCTION, OAM_DYNAMIC_YOUR_FUNCTION_TEXT, $cachedata);
  $text = OAM_your_function_filter_output();
  if ( $cachedata === 0 )
    define('OAM_DYNAMIC_YOUR_FUNCTION_TEXT', $text);
  else
    return str_replace( OAM_DYNAMIC_YOUR_FUNCTION, $text, $cachedata );
}

if(function_exists('add_cacheaction')) {
  add_cacheaction( 'wpsc_cachedata', 'OAM_your_function_filter' );
}

function OAM_your_function_filter_output() {
  $buffer = "";
  ob_start();
  echo "Dynamic output!"; 
  //You can call wp functions, or other plugin functions. 
  $buffer = ob_get_contents();
  ob_end_clean();
  return $buffer;
}

function OAM_your_function_safety( $safety ) {
  if ( defined('OAM_DYNAMIC_YOUR_FUNCTION_TEXT'))
    return 1;
  else
    return 0;
}

if(function_exists('add_cacheaction')) {
  add_cacheaction('wpsc_cachedata_safety', 'OAM_your_function_safety');
}