I just fell face forward into this earlier today (sorry for the extremely long lines):

use vars qw/                                                          
+                                                                     
+                           
$AllowFullYearView                                                    
+                                                                     
+                           
$LevelForRobotsDetection $LevelForWormsDetection $LevelForBrowsersDete
+ction $LevelForOSDetection $LevelForRefererAnalyze                   
+                           
$LevelForFileTypesDetection $LevelForSearchEnginesDetection $LevelForK
+eywordsDetection                                                     
+                           
/;
($AllowFullYearView,
 $LevelForRobotsDetection, $LevelForWormsDetection, $LevelForBrowsersD
+etection, $LevelForOSDetection, $LevelForRefererAnalyze,
 $LevelForFileTypesDetection, $LevelForSearchEnginesDetection, $LevelF
+orKeywordsDetection)=
  (2,2,0,2,2,2,2,2,2);
use vars qw/                                                          
+                                                                     
+                           
$DirLock $DirCgi $DirConfig $DirData $DirIcons $DirLang $AWScript $Arc
+hiveFileName                                                         
+                           
$AllowAccessFromWebToFollowingIPAddresses $HTMLHeadSection $HTMLEndSec
+tion $LinksToWhoIs $LinksToIPWhoIs                                   
+                           
$LogFile $LogType $LogFormat $LogSeparator $Logo $LogoLink $StyleSheet
+ $WrapperScript $SiteDomain                                          
+                           
$UseHTTPSLinkForUrl $URLQuerySeparators $URLWithAnchor $ErrorMessages 
+$ShowFlagLinks                                                       
+                           
/;
($DirLock, $DirCgi, $DirConfig, $DirData, $DirIcons, $DirLang, $AWScri
+pt, $ArchiveFileName,
 $AllowAccessFromWebToFollowingIPAddresses, $HTMLHeadSection, $HTMLEnd
+Section, $LinksToWhoIs, $LinksToIPWhoIs,
 $LogFile, $LogType, $LogFormat, $LogSeparator, $Logo, $LogoLink, $Sty
+leSheet, $WrapperScript, $SiteDomain,
 $UseHTTPSLinkForUrl, $URLQuerySeparators, $URLWithAnchor, $ErrorMessa
+ges, $ShowFlagLinks)=
 ('','','','','','','','','','','','','','','','','','','','','','',''
+,'','','','');
[download]

etc for several pages, followed by:

#---------------------------------------------------------------------
+---------                                                            
+                           
# Function:             Write on ouput header of HTML page            
+                                                                     
+                           
# Parameters:   None                                                  
+                                                                     
+                           
# Input:                %HTMLOutput $PluginMode $Expires $Lang $StyleS
+heet $HTMLHeadSection $PageCode $PageDir                             
+                           
# Output:               $HeaderHTMLSent=1                             
+                                                                     
+                           
# Return:               None                                          
+                                                                     
+                           
#---------------------------------------------------------------------
+---------                                                            
+                           
sub html_head {
  my $dir=$PageDir?'right':'left';
  if (scalar keys %HTMLOutput || $PluginMode) {
    my $MetaRobot=0;            # meta robots                         
+                                                                     
+                           
    my $periodtitle=" ($YearRequired".($MonthRequired ne 'all'?"-$Mont
+hRequired":"").")";
    # Write head section                                              
+                                                                     
+                           
    if ($BuildReportFormat eq 'xhtml' || $BuildReportFormat eq 'xml') 
+{
      if ($PageCode) {
        print "<?xml version=\"1.0\" encoding=\"$PageCode\"?>\n";
      } else {
        print "<?xml version=\"1.0\" encoding=\"iso-8859-1\"?>\n";
      }
      ;
      if ($FrameName ne 'index') {
        print "<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 Strict//E
+N\" \"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd\">\n";
      } else {
        print "<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 Frameset/
+/EN\" \"http://www.w3.org/TR/xhtml1/DTD/xhtml1-frameset.dtd\">\n";
      }
      print "<html xmlns=\"http://www.w3.org/1999/xhtml\" xml:lang=\"$
+Lang\">\n";
    } else {
      if ($FrameName ne 'index') {
        print "<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitio
+nal//EN\">\n\n";
      } else {
        print "<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Frameset/
+/EN\">\n\n";
      }
      print "<html lang='$Lang'".($PageDir?" dir='rtl'":"").">\n";
    }
    print "<head>\n";
 
    print "<meta name=\"generator\" content=\"AWStats $VERSION from co
+nfig file awstats.$SiteConfig.conf (http://awstats.sourceforge.net)\"
+ />\n";
 
    if ($MetaRobot) {
      print "<meta name=\"robots\" content=\"".($FrameName eq 'mainlef
+t'?'no':'')."index,nofollow\" />\n";
    } else {
      print "<meta name=\"robots\" content=\"noindex,nofollow\" />\n";
    }
[download]

and so on for more than 10,000 lines - in one file.

Note the way arguments are passed to a function: in global variables, and the neat way of printing just one line per print statement (OK: in all fairness later the author has discovered here-docs, but he has not refactored).
And of course it is a CGI program, but does not use CGI;.

I was trying to find a web-log-analyser tool with nice pictures for the PHBs, and google pointed me towards a site on sourceforge, where a well-documented tool was available in perl, with all the nice graphs management likes.

I recoiled in horror on looking inside the code and discovering a true treasure-trove for the perlmonks Pearls (or not) - a sample of which I just had to share.
I will now go on my way and find something better or (yuck) do it myself. Pity - it did look promising, and I am lazy and impatient.

All names withheld to protect the unnamed author.