Kramer vs. Kramer (1979)

I hesitate to label something that came out when I was in college as a "classic movie", but in many ways the label fits (and the truth be told, I went to college quite a long time ago.  I completely identify with the feeling that I thought getting old would take longer). It won best actor (Dustin Hoffman), Best Supporting Actress (Meryl Streep), Best Adapted Screenplay, Best Director and Best Picture. 
My memory of the film was consistent with the content, but the passing years have made it refreshingly surprising that a man solo parenting a child would stand out like it did almost 40 years ago.  The story is that Mrs. Kramer is desperately unhappy in her role as mother and wife, and she leaves the family home (or apartment, as this is New York City) and the care of their 6 year old boy is left in Mr. Kramer's very incapable hands.  She goes about getting back into the work force, where she had been prior to her marriage, and where she finds her way back to her usual self. He finds his way into parenthood, and it is all well and good until she wants custody.  There are some things that are completely unrealistic about this, like how Mr. Kramer manages without any hired help, but it is a very well done window into a time of transition in work and family life in America.