[The_Cyberdemon]

Umm, do something like this on your index.php file:

$numbersthreads=$DB_site->query_first('SELECT COUNT(*) AS threads,MAX(threadid) AS maxthread FROM thread WHERE forumid=1');
$numberthreads=number_format($numbersthreads['threads']);
$getnewestthreadforum=$DB_site->query_first("SELECT threadid,title FROM thread WHERE threadid=$numbersthreads[maxthread]");
$newthread=$getnewestthreadforum['title'];
$newthreadid=$getnewestthreadforum['threadid'];

Replace 1 with the forumid of your choice.
Then, in the FORUMHOME template, put this wherever you want it:

Newest Thread in Forum forum name:
<a href="showthread.php?s=$session[sessionhash]&threadid=$newthreadid">$newthread</a>

That should work. If you get an invalid URL, try:
<a href=\"showthread.php?s=$session[sessionhash]&threadid=$newthreadid\">$newthread</a>
Instead of:
<a href="showthread.php?s=$session[sessionhash]&threadid=$newthreadid">$newthread</a>

Hope that helps.