As an artistic event, Nutcracker does practically everything but crack nuts. The Tchaikovsky ballet provides a holiday tradition for families, a rite of passage for aspiring young dancers, and a kind of outreach program for ballet companies nationwide. This year’s Atlanta Ballet production of Nutcracker features about 250 young area dancers in small roles, in addition to the company’s cast of professionals. When I arrived at Saturday’s matinee, I ran into a family friend who proudly pointed out that her daughter was one of the “party children” for that performance. More…