I've lived in California all my life and I'm traveling to Vietnam for the first time in a few days. What places should I visit?

My parents are originally from Vietnam but haven't been back since 1975. I will be in Hanoi 7/12-7/16, Hoi An 7/16-7/20, Saigon 7/20-7/24, Nhatrang 7/24-7/27, and back to Hanoi 7/27-7/29.

I am twenty years ago, and will be traveling with a few cousins my age. What are some good local hangout spots in the above mentioned cities?

Also, The Dark Knight Rises comes out on 7/20 while I'm in Saigon... will any movie theaters be showing it? In English?

Thanks!