Well, Pontifex is an encryption schema from the book Cryptonomicon (which is really good, btw).  Just thought I'd share:
[pre]#!/usr/bin/perl -s

$f = $d ? -1 : 1;
$D = pack('C*', 33..86);
$p = shift;
$p = ~y/A-Z/;
$U = '$D = ~s/(.*)u$/U$1/; $D = ~s/U(.)/$1U/;';
($V = $U) = ~s/U/V/g;
$p = ~s/[A-Z]/$k = ord(#&) - 64, & e/eg;
$k = 0;

while(<>)
{
    y/a-z/A-Z/;
    y/A=Z//dc;
    $o .= $_
} $o .= 'X'

while length($o) %5 && !$d;

$o = ~s/./chr(($f * &e + ord($&) - 13) %26 + 65/eg;
$o = ~s/X*$// if $d;
$o = ~s /.{5}/$& /g;
print "$o\n";

sub v
{
    $v = ord(substr($D, $_[0])) - 32;
    $v > 53 ? 53 : $v;
}

sub w
{
    eval "$U$V$V";
    $D = ~s/(.*)([UV].*[UV])(.*)/$3$2$1/;
    &w(&v(53));
    $k ? (&w($k)) : ($c = &v(&v(0)), $c > 52 ? &e : $c)
}[/pre]

Actually, I'm not even sure if it works, but it looks interesting!

It looks incredibly difficult to follow, but I dont know Perl either.

There are many lines in it that look like they're there solely to make it difficult to understand the code.  They do operations that could very easily be done a different way in a complex way.  That's not a good sign for an encryption scheme.

Also, how does it work?  Where is the key and what is it encrypting? 

The key is user supplied, and it encrypts plaintext.  An example is here.

The official page is here, which supplies a much better Perl implementation, as well as 16 other implementations in 13 languages.

[quote author=rabbit link=topic=13920.msg141933#msg141933 date=1137349675]
The key is user supplied, and it encrypts plaintext.  An example is here.
[/quote]

Why, exactly, do I get a JavaScript error, "ActiveXObject Undefined"?  That's ewwy :)

[quote author=iago link=topic=13920.msg141934#msg141934 date=1137352418]
[quote author=rabbit link=topic=13920.msg141933#msg141933 date=1137349675]
The key is user supplied, and it encrypts plaintext.  An example is here.
[/quote]

Why, exactly, do I get a JavaScript error, "ActiveXObject Undefined"?  That's ewwy :)
[/quote]

It doesn't work at all for me. I don't even receive an error. What browser are you using? I'm on Mozilla Suite.

Old link.  Try the new one.

It didn't work for me in Firefox, so I looked (and found) a new one:

http://www.erobillard.com/Content/solitaire/

The reason it didn't work was that it was in (eww!) ActiveX :)

Yeah.  Eww indeed.  It doesn't even really match what the original scheme was anyway :\  O well.

I read Cryptonomicon, and I found it sucky. You wasted ten of my dollars, rabbit :(

Pfft!  You obviously suck at life then.  Cryptonomicon is awesome.