collapsor:

		/*
		* collapsor (1.0) // 2008.04.05 // <http://plugins.jquery.com/project/collapsor>
		* 
		* REQUIRES jQuery 1.1.2+ <http://jquery.com/>
		* 
		* Copyright (c) 2008 TrafficBroker <http://www.trafficbroker.co.uk>
		* Licensed under GPL and MIT licenses
		* 
		* collapsor opens and closes sublevel elements, like a collapsable menu
		*
		* We need to select the clickable elements that trigger the opening action of the sublevels: $('#menu ul li a').collapsor();
		* The sublevel element must be in the same level than the triggers
		*
		* Sample Configuration:
		* $('ul a').collapsor();
		* 
		* Config Options:
		* activeClass: Class added to the element when is active // Default: 'active'
		* openClass: Class added to the element when is open // Default: 'open'
		* sublevelElement: Element that must open or close // Default: 'ul'
		* speed: Speed for the opening animation // Default: 500
		* easing: Easing for the opening animation. Other than 'swing' or 'linear' must be provided by plugin // Default: 'swing'
		* 
		* We can override the defaults with:
		* $.fn.collapsor.defaults.speed = 1000;
		* 
		* @param  settings  An object with configuration options
		* @author    Jesus Carrera <jesus.carrera@trafficbroker.co.uk>
		*/
	

collapsor samples:

		HTML:
		<ul>
			<li>
				<a href="#menu_1">Menu 1</a>
				<ul>
					<li>
						<a href="#menu_1_1">Menu 1-1</a>
					</li>
					<li>
						<a href="#menu_1_2">Menu 1-2</a>
						<ul>
							<li>
								<a href="#menu_1_2_1">Menu 1-2-1</a>
							</li>
							<li>
								<a href="#menu_1_2_2">Menu 1-2-2</a>
							</li>
						</ul>
					</li>
				</ul>
			</li>
			<li>
				<a href="#menu_2">Menu 2</a>
			</li>
			<li>
				<a href="#menu_3">Menu 3</a>
			</li>
		</ul>
		
		JS:
		$('ul a').collapsor();
	

• Menu 1
  • Menu 1-1
  • Menu 1-2
    • Menu 1-2-1
    • Menu 1-2-2
• Menu 2
• Menu 3

		HTML:
		<dl>
			<dt>
				Level 1
			</dt>
			<dd>
				Level 1 desc
			</dd>
			<dt>
				Level 2
			</dt>
			<dd>
				<strong>Level 2 desc</strong>
				<dl>
					<dt>
						Sublevel 1
					</dt>
					<dd>
						Sublevel 1 desc
					</dd>
				</dl>
			</dd>
		</dl>
		
		JS:
		$('dl strong').collapsor({sublevelElement:'dl', speed: 1000});
	

Level 1

Level 1 desc

Level 2

Level 2 desc

Sublevel 1

Sublevel 1 desc