Menus are contained within the CSSList module. You can pull down CSSList from the YUI Gallery. Just include this in your head.
The latest (unstable) is on Github, and available for forking.
You can mark the active list element by adding the .yui3-menu-active class to the list element.
Adding dropdowns to menus requires the use of JavaScript. The Y.Menu module adds dropdown functionality and the ability to create JavaScript menus. It uses csslist to style these menus, so they look identical.
Fixed menus can be created by adding the yui3-menu-fixed class name to the wrapper. This will fix a menu to the top of the page.
Paginators are list-based elements too! You can implement a paginator control by adding the .yui3-paginator classname to a ul element. Paginator controls generally look like buttons, but omit the yui3-button class name if you want simple paginators.