From the Rules:
"The Box Office theatrical board game is based on producing plays for the stage. As a player, you become a producer seeking to win by earning the most money by producing plays."
"The Box Office theatrical board game has been developed by Canadian Cultural Consultants Corporation as a fund raising tool for Canadian and American theaters."
As producers, players move around the board, which represents various North American theaters, seeking to produce plays to which they own the rights. If producers don't have the right compliment of actors in their "stable", they may have to barter with other producers to borrow an actor with the right talents.
Another part of the game board are a few 'Make Or Break' spaces, which add in a number of random events, such as losing or gaining an actor, or added box office revenues.
Winner is the producer who first reaches a certain dollar number, which the players pre-determine.
Rules specify four players, don't know why it couldn't be played with fewer.