Wiktionary
n. A session in a club, theatre etc. in which amateurs perform, rather than professionals.
Wikipedia
Amateur Night (formerly known as Drive, She Said) is a 2016 American comedy film written and directed by Lisa Addario and Joe Syracuse. Their early experiences in Hollywood were the basis for the plot of the film. The film stars Jason Biggs, Janet Montgomery and Ashley Tisdale. It is also the feature debut for Eddie Murphy's daughter, Bria Murphy.
Usage examples of "amateur night".
The Sunday papers 'd like to get Amateur Night done up brown in a nice little package, and the manager don't see it that way.
After Ali Bakhtiar's virtuoso displays of superciliosity, this was amateur night.
But he had them kidnap Dash, in a real amateur night kidnapping without any plans for what they were going to do with the boy, hoping to blackmail me by threats against the boy with playing along with his game.
They announced they were going to a strip club near the airport for amateur night.