As the legend goes, Bach's Goldberg Variationswere written for an insomniac diplomat patron who desired music to help cheer him on lonely, sleepless nights. But the real legend is how Bach was able to produce, for an apparently throwaway occasion, one of the crowning masterpieces not only of the Baroque, but of all Western music. Here's a gathering of widely varied interpretations the music has inspired, from keyboard masters to arrangements for string orchestra, jazz trio, and even brass band.