It's a very famous play written by Oscar Wilde.
Wilde was a gay man at a time when being gay was illegal. And he paid the price for this, spending TWO years in prison for "offence" of being a homosexual!
Although none of the characters in 'The Importance of Being Earnest' (TIoBE) are gay, Wilde clearly uses the characters to poke fun at ignorant people and so-called 'traditional values'. All of this is done in a hilarious way. Why not watch the clip below to get a sense of the wit.
Jack Worthing comes to London to escape county life under the name of Ernest. While in London, he falls in love with Gwendolyn, much to the annoyance of Lady Bracknell.
Algernon Moncrieff, Jack's friend, learns of his country life and goes to investigate. While in the country, Algernon pretends to be Ernest and falls for Cecily.
When all the lovers come together, hijinks ensue.
IT'S HONESTLY VERY FUNNY!