I know how naive I seem asking this question but was far too fascinated by the character JARVISJARVIS in the Iron Man movies to not ask this.
Well JARVIS is nothing but Tony Stark's personal assistant that happens to be a computer program with amazing AI(Artificial Intelligence) and has a personality of its own. In Peter David's novelization of the film, JARVIS is revealed as an acronym for Just A Rather Very Intelligent System.
Technically speaking, does such a real world system exist? If yes, please do provide concrete references. If not (I bet), how close a system has been developed? (references again!)