function txx_top_posts_mu( $howMany = 10 ) {
global $wpdb;
global $table_prefix;

// get an array of the table names that our posts will be in
// we do this by first getting all of our blog ids and then forming the name of the
// table and putting it into an array
$rows = $wpdb->get_results( "SELECT blog_id from $wpdb->blogs WHERE
    public = '1' AND archived = '0' AND mature = '0' AND spam = '0' AND deleted = '0';" );
if ( $rows ) :
    $blogPostTableNames = array();
    foreach ( $rows as $row ) :
        $blogPostTableNames[$row->blog_id] = $wpdb->get_blog_prefix( $row->blog_id ) . 'posts';
    endforeach;
    //print_r($blogPostTableNames);

    // now we need to do a query to get all the posts from all our blogs
    // ordered by the number of comments and with limits applied
    if ( count( $blogPostTableNames ) > 0 ) :
        $query = '';
        $i = 0;
        foreach ( $blogPostTableNames as $blogId => $tableName ) :
            if ( $i > 0 ) :
                $query.= ' UNION ';
            endif;
            $query.= " SELECT ID, comment_count, $blogId as `blog_id` FROM $tableName ";
            $i++;
        endforeach;
        $query.= " ORDER BY comment_count DESC LIMIT 0,$howMany;";
        //echo $query;
        $rows = $wpdb->get_results( $query );

        // now we need to get each of our posts into an array and return them
        if ( $rows ) :
            $posts = array();
            foreach ( $rows as $row ) :
                $posts[] = get_blog_post( $row->blog_id, $row->ID );
            endforeach;
            //print_r($posts);
            return $posts;
        endif;
    endif;
endif;
return false;
}