n. A piece of jazz music that involves musicians playing extremely fast runs (usually during solos) throughout the song, as if the musicians were on crack, speed, or some other stimulant drug when they recorded the song.
Listen to some Miles Davis and John Coltrane recordings if you want to listen to classic "crack jazz". For a more modern example, look up songs by the New York Big Band on Youtube.
by Jimmy "Sax Machine" Phillips July 13, 2009