// Run this when the document finishes loading.
$(document).ready( function() {

    // Mouseover
    $(".menu_li").mouseover( function() {
        $(this).stop().animate( { height: '90px' }, { queue: false, duration: 300 } )
    } );

    // Mouseout
    $(".menu_li").mouseout( function() {
        $(this).stop().animate( { height: '20px' }, { queue: false, duration: 300 } )
    } );

} );