Do you know ghouls from goblins and ghosts?
Standard way of suggesting that someone has succumbed to terminal geekdom. Often heard on Usenet, especially as a way of suggesting that the target is taking some obscure issue of theology too seriously. This exhortation was popularised by William Shatner on a "Saturday Night Live" episode in a speech that ended "Get a *life*!", but some respondents believe it to have been in use before then. It was certainly in wide use among hackers for at least five years before achieving mainstream currency in early 1992.