Exclude newest post from category X but show rest

A while back i posted a simple function that gets latest post in a certain category:

function get_lastest_post_of_category($cat){
    $args = array( 'posts_per_page' => 1, 'order'=> 'DESC', 'orderby' => 'date', 'category__in' => (array)$cat);
    $post_is = get_posts( $args );
    return $post_is[0]->ID;
}

So once you have that function you can use use WP_Query or query_posts and using the post__not_in parameter you can exclude that post, so something like:

query_posts(array(`post__not_in` => array(get_lastest_post_of_category($CAT_ID))));

just change $CAT_ID to the actual category id