(adj.) to be biboybandal is to be a fan of both *NSYNC and Backstreet Boys; to like both musical groups equally and not favor one over the other. It can also be used more generally to refer to any two boy bands (i.e. New Kids on the Block, 98 degrees, O-Town, etc.).
My friends always fought over which boy band they thought was better. I never had that problem myself, being biboybandal, so I would mediate their arguments by bringing up the many talents that each group possessed.