Most obfuscated piece of macro you know

From: Zakath (I_hate_spam_at_laposte.net)
Date: 03/29/05 

Date: Tue, 29 Mar 2005 07:11:59 +0200

Hi,

I am still a Lisp beginner but I played quite a lot with macros. It
is a very powerful tool but I also discovered that, as a
side-effect, it can make your code look more cryptic.

That leads us to the following question : what is the most
obscure/obfuscated piece of macro you, dear Lisp hackers, have ever
seen ?

Thanks in advance

Zakath