The GiantDropdown jQuery plugin replaces the standard HTML select list with an unordered list (UL) that's easily styleable for a custom presentation of selectable items. It's called the Giant Dropdown because it was originally designed to support dropdown items that are very long and which expand a dropdown to an unreasonable size.
The Giant Dropdown hides your original select list and adds an unordered list in its place. The UL uses the original select element as its backing data store so any events, data validations, and postback information should still work exactly as designed without modification.
This repository includes a working sample of how to use the Giant Dropdown. You can see another demo on my blog.
The plugin is in the scripts folder.