CSS Dropdown Menu

http://www.cssmenumaker.com/builder/menu_info.php?menu=057

http://www.cssmenumaker.com/drop_down_css_menu.php

http://www.cssmenumaker.com/

http://www.izzymenu.com/build.php

http://www.1stwebdesigner.com/resources/38-jquery-and-css-drop-down-multi-level-menu-solutions/

http://www.webdesigndev.com/web-development/create-the-fanciest-dropdown-menu-you-ever-saw - really cool

http://free-css-menu.com/mootools-slide-menu-css3.html

http://www.sohtanaka.com/web-design/mega-drop-downs-w-css-jquery/ - Mega Dropdown menu

DRILL DOWN

http://www.dynamicdrive.com/dynamicindex1/drilldownmenu.htm#

http://www.filamentgroup.com/lab/jquery_ipod_style_drilldown_menu - drilldown menu

http://radixdvd.com/free-css-menu/bdc-drilldown-menu.html

CHAINED SELECT

http://www.dynamicdrive.com/dynamicindex1/chainedmenu/index.htm

Javascript