Ciao, prova così:
Codice PHP:
<?php 
$query_read2 
mysql_query("SELECT * FROM giochi_files WHERE cat_id != 'sexy'   ORDER BY RAND()  DESC limit 0,6  ") ;
$n=0
while(
$riga_read2 mysql_fetch_array($query_read2)) { 
$n++;
"""    variabili di estrazione"""" 

?> 
<div style="
width:145pxtext-align:centerfont-size:10pxheight:90pxmargin:5px;" <?php if($n%3==0) echo "class='top'";?> >[url="<? echo "]/giochi-gratis-flash/<? echo "$cat_id_read"; ?>/<? echo "$id_read"; ?>_<? echo "$nome_read_"; ?>.html" title="<? echo "$nome_read_"; ?>">[img]<? echo [/img]/images/giochi-flash/<? echo "$immagine_read"?>" border="0" title="giochi online gratis <? echo "$nome_read"?>, categoria <? echo "$cat_id_read"?>" width="145" height="90" style="border:1px solid #CCC; padding:4px;" />[/url]</div> 
<?php 

?>