If you use
<pre><?php print_r($wp_query->query_vars); ?></pre>
to display the query var array and decide to use one of the elements, here are some simple examples the get_query_var() function that outputs them.
<?php $curcat = get_query_var('category_name'); $curtax = get_query_var('taxonomy'); $curterm = get_query_var('term'); ?>