$(document).ready(function() {

    $('#menu>ul>li>ul').hide();
    $('#menu>ul>li').mouseover(function(){
        // create a reference to the active element (this)
        // so we don't have to keep creating a jQuery object
        $heading = $(this);
        // check to see if any sub menus are open
        if ($heading.siblings().find('ul:visible').size()!=0) {
            // close open sub menus
            $heading.siblings().find('ul:visible').slideUp(500, function(){
                // open current menu if it's closed
                $heading.find('ul:hidden').slideDown(500);
            });
        }
        else {
            // open current menu if it's closed
            $heading.find('ul:hidden').slideDown(500);
        }
    })

    $('a.external').attr('target', '_blank');

});