<html>
<body>
<ul>
<li><a href = "http://google.ru">google</a></li>
<li><a href = "http://ya.ru">ya</a></li>
<li><a href = "http://javascript.ru">javascript</a></li>
</ul>
<button onclick = "location = document.links[Math.floor(Math.random() * document.links.length)]"> follow random link </button>
</body>
</html>