In his wonderfully ambiguous One Minute Sculptures, which are only humorous at first glance, the Vienna-based conceptualist, Erwin Wurm, takes a literal approach to sculpture while also taking the medium apart: anyone can be a piece of art for a minute by following his instructions. The non-human works by which he is best known, the overinflated and floppy Fat Car and Fat House, are likewise spirited, thoughtful critiques, in...