<!-- The HTML -->
<div class="w">
    <ul>
        <li>Elemento 1</li>
        <li>Elemento 2</li>
        <li>Elemento 2</li>
    </ul>
</div>

<!-- The CSS -->
<style type="text/css">
.w { overflow:hidden; }
ul { float:left; left:50%; position:relative; }
li { float:left; right:50%; position:relative; }
</style>

http://jsfiddle.net/Alwaison/n3YaC/

A *ul* or *ol* list centered in the container.

Horizontal navigation centered in their container

css, html

HTML