I've been searching all over the place, but can't seem to find an example of
what I'm trying to do. Hoping someone here can point me in the right direction.

Essentially, I'm trying to create progressive menus like this:

http://www.napaonline.com/MasterPages/NOLMaster.aspx?PageId=421

But rather than using select menus, I would like to do it with nested unordered
lists. Here's some basic sample code:

<ul>
<li><h2><a href="#">Apparel</a></h2>
<ul>
<li>Shoes</li>
<li>Denim</li>
<li>Underwear</li>
</ul>
</li>

<li><h2><a href="#">Electronics</a></h2>
<ul>
<li>TV's</li>
<li>Stereos</li>
<li>Games</li>
</ul>
</li>
</ul>

So in this example, "Apparel" and "Electronics" are visible items in the popup
menu, and the submenu items are hidden. If the user clicks on "Apparel" a second
popup menu appears next to it containing "Shoes", "Denim", "Underwear".

Anyone know how I might accomplish this?