I especially enjoy this aspect of Mason. Not the reason I'm using it, and I'm not sure the overhead would be worth it for just this feature, but it's worth a look.

Mason does this by jumping in and handling certain URLs, then parsing them to try and find the best match for the request. No need to state parameters explicitly with a ? or reveal the handler's name in the URL. It can even be configured in a local .htaccess file if you're working with apache in an environment where you don't have access to the httpd.conf.

Assuming apache, here's an example .htaccess:

order allow,deny
allow from all

Options -Indexes -ExecCGI

#Server root relevant path to handler script
Action my-handler /test/my_handler.pl

SetHandler my-handler

AddHandler default-handler .html .gif .jpg .png

<FilesMatch "my_handler.pl$">
 Options +ExecCGI
 SetHandler cgi-script
</FilesMatch>
[download]

And an example my_handler.pl- not very useful as is, but dispatch with your new parameters as you like:

#!/usr/bin/perl -wT
use strict;

print "Content-type: text/html\n\n";

print "<p>Request_URI contained: " . join( ' ', map {"[$_]"} split '/'
+, $ENV{REQUEST_URI}) . "</p>\n"; 
print "$_ => $ENV{$_}<br />\n" for sort keys %ENV;
[download]

Don't forget that the parameters will be encoded...