abCD1234%^&* might be a good example of using special characters in a password (though obviously you'd want something more random than that sequence), consider this password: äßÇн²¶╔¥¢. I'd love to see the password cracker that can crack that one. :-)
Of course, as the author mentions there are downsides to this. Increased complexity notwithstanding, its strength is also its main weakness; these are non-standard characters, and as such not all applications and operating support them in the same manner (or at all). While this may work great as a Windows user password, for example, it may not be possible to use it as a Linux user password.
Regardless, it's still an interesting concept that deserves some attention. Check out the article for more details on the subject, as well as a tutorial and reference charts for entering special characters. The Wikipedia article on Windows Alt keycodes (also referenced in the article) is another good resource.