When do the words 'house' and 'garage' cause the RIBA's old guard to feel slightly nervous? The answer: when they are linked to the words 'night' and 'club'. Some RIBA members heading towards the institute's conference in July are already starting to get twitchy, following the announcement that this year's Urban Ball will be held in Bristol's Ministry of Sound. It is billed, rather frighteningly, by George Ferguson as his last 'Big Bang'. And, no, 'hard core' is not an aggregate. . .