well using the following wGET command line retrieved about 4.5 megs of info
from that site, before I interrupted it with CTL-C.

wget --user-agent="Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)"
--output-file logfile.txt -PPHPBB -r -l2
<http://www.phpbb.com/community/viewforum.php?f=6>

The only problem with wGET is that those PHP files don't get saved as HTML,
but you could write a script to peek at all those files and see if they have
the DOCTYPE HTML at the top.

You'd have to look a the wGET manual and see if you can get the links to
reflect those files too.