Как вариант...
<!DOCTYPE html>
<html>
<head>
<script src="http://code.jquery.com/jquery-latest.js"></script>
<!--
<link rel="stylesheet" type="text/css" href="tmp.css" />
-->
<style type="text/css">
</style>
<script type="text/javascript">
$(document).ready(function(){
$('a').mouseover(function(){
var a=['red', 'silver', 'orange', 'blue']
var i=Math.floor(Math.random()*a.length)
$(this).css('color',a[i])
})
})
</script>
</head>
<body>
<a>А</a>
<a>Б</a>
<a>В</a>
</body>
</html>