Simple menu with sub-levels
Some suggestions:


Use var when declaring variables, unless you really want to make global variables (which you probably don't)
Combine var statements using ,

var a = 1, b = 2, c = 3;

Combine classes in toggleClass

$(this).toggleClass('minus expand')

Cache selectors that are used often (like $('#main'))
You don't need to use $li2 inside the click handler, you can just use $(this)
Turn repeated code into a function




$(function(){
    var $main = ('#main'),
    slide = function(ele, find){
        return $(ele).toggleClass('minus expand').find(find).delay(200).slideToggle(400);
    },
    $li = $('&gt; li.expand', $main).click(function(){
        var $ul = slide(this, 'ul.sub-level');
        $('&gt; li &gt; ul', $main).not($ul).slideUp('slow');
        $('&gt; li.minus', $main).not(this).toggleClass('minus expand')
    }),
    $li2 = $('.sub-level &gt; li.expand').click(function(){
       slide(this, 'ul.sub-level2');
    });
});