This theater organizational diagram works best for their specific needs; however, some common roles found in most theater companies include a board of trustees, and artistic director, a managing director, a development director, and non-permanent positions such as a technical director, technical crew, directors, musical directors, choreographers, actors, and musicians. Some businesses also employ publicists and box office managers. Plays and musicals are performed in modern theater. Ballet and opera are both forms of theater that use many conventions such as acting, costumes, and staging.