It seems most people here are using 'conceptual' in away not generally associated with Art. That's OK, and I don't want to start any war or anything like that. But I do think with a 'conceptual' work the idea is normally more important than the media, or some story or mood. A concept is not a mood or a story, and relatively 'cool'. And the source material is really irrelevant – or should be – Duchamp's urinal for instance. I'm not sure then why the term is being used in these other cases? I guess the term is just banded around like in the case of the YBAs.
"Conceptual art, also referred to as conceptualism, is art in which the concept(s) or idea(s) involved in the work take precedence over traditional aesthetic, technical, and material concerns. Some works of conceptual art, sometimes called installations, may be constructed by anyone simply by following a set of written instructions. This method was fundamental to American artist Sol LeWitt's definition of conceptual art, one of the first to appear in print:
"In conceptual art the idea or concept is the most important aspect of the work. When an artist uses a conceptual form of art, it means that all of the planning and decisions are made beforehand and the execution is a perfunctory affair. The idea becomes a machine that makes the art.""
In the Blink of an Ear: Toward a Non-cochlear Sonic Art by Seth Kim-Cohen - ?