Before watching the movie:
The title pretty much says it all. There’s a plot about high schoolers and some kind of competition, but this is basically a concert film.
The cast is full of appearances from acts who were famous in their day, but the main name I recognize now is Chuck Berry, and I think I’ve seen much more of him now than at the top of his career, so that will be interesting. When I think of Chuck Berry in the 50s, I think of Marty McFly.