All are correct.
1 - 6 mean approximately the same thing.
7 is a bit different; the speaker could be including him/herself or not. It's not clear.
1. How about going to see a movie?
2. Why don't we go to see a movie?
3. Why not go to see a movie?
4. Shall we go to see a movie?
5. What do you say to seeing a movie?
6. Let's go to see a movie.
7. Why don't you go to see a movie?
================
Are they all grammatical and the same? Are they all interchangable?
1 answer