function expand(obj){
	$$('#main-nav li ul').invoke('hide');
	$$('#main-nav li a').each(function(s) { if(s.next('ul')) s.setStyle({background:'none', color:'#fff'}); });
	obj.setStyle({
		backgroundColor:'#e4e4e4',
		color:'#666'
		});
	Element.show(obj.next());
	}
	
function fold(obj,sibs){
	var s = Element.nextSiblings(obj.parentNode.parentNode)
	for(i=0; i<sibs; i++){
		if(s[i].visible()) s[i].hide();
		  	else s[i].show();
		}
	}