$(document).ready(function() {

    $( "ul.navigation > li" ).each( function() {        
        
        $( this ).hover( function() {
        
            $( this ).children( "ul" ).slideDown( 0 );
        
        },
        
        function(e) {
        
            $( this ).children( "ul" ).slideUp( 0 );
        
        });                                    
                                
    });   

});