[rich! @ etiviti]

there is no action on the forums/index.php theme page above the forum-loop. I think this might be an error though. So you would need to move do_action( 'bp_directory_forums_content' ) above the forums-loop div

for the desc, just wrap it in

bp_create_excerpt( $listing->forum_desc, 255)

(where 255 is the limit – i’ll also add this to the forum index widget too)