I just learned quite a bit reading this thread. I had no idea about the below:

Shirley/Warren
Eric/Julia (Well, I actually just found that out a week or two ago)
Astin/Duke

You learn something new every day.

One that surprised me that I didn't see listed:
Vanessa Redgrave, Natasha Richardson, and Joely Richardson. I see the name thing for the sisters, but they don't look anything alike to me. And I had no idea that was their mother.