When I think back on the past several years, as to whether there was any artist who came forward with a move that resonated in that the-world-before-and-after, you-can-only-do-it-once sort of way (like say, Duchamp's submission of a urinal to the Salon Des Independants): well, the only thing that really jumps to mind is Urs Fischer's excavation of the entire floor of the Gavin Brown Enterprise gallery. The massive crater he produced out of a piece of pricey NY real estate (an exhibit entitled "You"), and the corollary threat of at least disorientation, and possibly bodily harm it presented to any potential visitor, had an air of the pure, sexy media stunt to be sure. But mixed in it was a punk's menacing sneer, and a subversive spark of Zen: the refusal to comply with the fundamental presuppositions of the cultural game, and present a piece of the void instead. And it made for an oddly sublime image...
If anyone's topped that since, well, who was it? In my book, You's the thing to beat.