Oliver Goldsmith's play She Stoops to Conquer may have first been called Mistakes of a Night because the play centers around one night in the lives of its characters and that night is indeed filled with mistakes.
The whole thing begins when Marlow and Hastings travel out to the Hardcastle house to court Kate and Constance. Tom meets the two young men (who by this time are thoroughly lost) at the pub and decides that he will trick them into thinking that the Hardcastle home is actually an inn. They fall for it, and they make the mistake of treating Mr. Hardcastle as an innkeeper. He is not at all happy about such treatment.
As the play continues, Hastings learns the truth about where he is, but he and Constance decide to keep that knowledge from Marlow, who is nervous enough about courting Kate. This is probably a mistake, but it does keep Marlow in place. Of course, Marlow actually manages to fall all over himself in his nervousness and makes a relatively poor impression on Kate. She thinks that she could like him if he weren't so anxious.
In the meantime, Hastings and Constance decide that they want to elope, but Constance won't leave without her jewels. They get Tony to swipe the jewels from Mrs. Hardcastle. He gives the jewels to Hastings, who in turn entrusts them to Marlow. But Marlow makes the mistake of giving them back to Mrs. Hardcastle for safekeeping, thus completely messing up the plan.
The hilarity continues as Marlow, still thinking he is at an inn, mistakes Kate for a barmaid. He actually feels a lot more comfortable around a barmaid than an upper-class lady, so he flirts with Kate and tries to kiss her.
Tony receives a note from Hastings about the plot between Hastings and Constance, but since Tony cannot read, he foolishly gives to note to Mrs. Hardcastle to read for him. Because of this, she finds out about their intent to elope.
Everything ends well eventually, but the whole play is indeed a night of mistakes.