mm_forum

here an example patch:

//patch start
$forum_id = (isset($this->conf['listLatest.']['forum_id'])) ? ' AND f.uid = '.intval($this->conf['listLatest.']['forum_id']).' ' : '';
//patch end

        $res = $GLOBALS['TYPO3_DB']->exec_SELECTquery(
            't.topic_last_post_id as post_id, t.uid as topic_id, t.*,
                f.uid as forum_id, f.forum_name as forum_name,
                c.forum_name as category_name,
                p.poster_id as author, p.post_time',
            'tx_mmforum_posts p, tx_mmforum_forums f, tx_mmforum_forums c, tx_mmforum_topics t',
            't.uid = p.topic_id AND
              p.uid = t.topic_last_post_id AND
                f.uid = p.forum_id AND
                c.uid = f.parentID AND
                p.deleted = 0 AND t.deleted = 0 AND f.deleted = 0 AND c.deleted = 0 AND
                p.hidden  = 0 AND t.hidden  = 0 AND f.hidden  = 0 AND c.hidden  = 0 '.
//patch start                
$forum_id.
//patch end
                $this->getMayRead_forum_query('f').
                $this->getMayRead_forum_query('c').
                $this->getCategoryLimit_query('c'),
            'p.topic_id',
            'p.post_time DESC',
            $limit
        );

but a comma separated list would even be better.