BuddyPress.org

If you’re comfortable with the loop, check out the bp_has_forum_topics() function located in /buddypress/bp-forums/bp-forums-templatetags.php.

Unfortunately this isn’t documented in the BP codex, but if you check out /bp-themes/bp-default/forums/forums-loop.php, you should have a good idea of how to construct a recent topics loop.

Hope that gives you a few pointers to go on.