Madonna makes her West End debut at the Wyndham theatre in Up for Grabs a comic satire on the art world, in which she plays an art dealer pitting one client against another in a bidding war over a Jackson Pollock painting. And Pollock is also the subject of a new biographical film directed by and starring Ed Harris in the title role. Tom Sutcliffe and guests give their verdicts on theseand other cultural highlights of the week. Producer Mohini Patel