Qualcosa saprebbe dirmi perche nn funziona il seguente codice?

codice:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js" type="text/javascript"></script>
<script>
$('#Apri').ready(function() { alert('ci passo');
  $('#Apri').children.slideDown('slow');
});
</script>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
</head>

<body>

	
                      
                        	<div id="sub_menu2">
                            	<ul class="sub_menu">
                              		
                                    	<div id="Apri">
                            				<ul class="sub_menu">
                              					[*]Prova Link
                                				[*]Prova Link
                                				<li class="last">Test
                           					[/list]
                            			</div>
                                   
                                	[*]Prova Link
                                	<li class="last">Test
                           		[/list]
                            </div>
                        
                         
</body>
</html>