Something

<?php
/*
Created by Ludek Uiberlay aka ne0 (or wendig0)
http://ludek.biz/
http://www.last.fm/user/wendig0/

Feel free to use this code - but not for faking! :)

Don't forget to change a date...
*/

$string = ""; // last.fm winamp audioscrobbler 1.1.10 cache - here insert cache...
$string = explode (" MP3  ",$string);
for ($i = 1; $i <= 617; $i++) {
   $time = time() + ($i*30);
   $date = date('H:i:s',$time);
   $string[$i] = Ereg_replace(
   "2006-07-0(.) (..):(..):(..)",
   "2006-07-10 ".$date,
    $string[$i]);
}
$string = implode(" MP3  ",$string);

$fp = FOpen("audioscrobbler.99.cache", w);
FWrite($fp, $string);

echo "Enjoy!";
?>