No brown M&Ms - The Chive has a list of some of the backstage demands by various musicians.  Britney Spears, for example, wants a framed photo of Princess Di.  I read somewhere that Van Halen buried the "no brown M&Ms" clause in their contract as a way to determine if promoters actually read it.  If they saw brown M&Ms, it was a sign that there was a good chance that their very-heavy stage equipment could fall through the floor.