On the light side — and no, this has nothing to do with computer viruses — there's a wonderful video on YouTube, showing some guys in Australia taking a real Trojan horse (dead link; see below) around and seeing where they can manage to leave it overnight. Have a look. I got a good laugh from it.
Update, 12 Mar: That video violated copyright, so YouTube took it down. Commenter Donna found this link on the Australian network directly, so maybe it'll last longer. Thanks Donna!