Anyone see a musical while it was still in early stages of production?

I saw Swept Away at Berkeley Repertory a few years ago, and I was really excited to listen to the OBC when it was released! I had such a good time thinking about what I saw versus the changes they made for the show now, and I was curious if anyone else got to see/witness a transformation of a different show.

Share your experiences below please! I wanna see how art changes over time.