Also the name given to many SF parties after conventions or meetings. They are apparently called dead dogs because everyone stays up until they are dog-tired, or something of that nature.
Fandom, as all the fans of SF, Fantasy, the SCA, Trekies, and so on are called, is known for liking to stay up late drinking fizzy drinks of various types and discussing the minutia of their topic of interest and many other things besides. More than a few times I have found myself debating the causes of the decline of the Roman Empire at 2am with some fan.