A play by David Hirson, first produced on Broadway in 1991. It won several awards, and was nominated for several Tonies, but had a fairly short run. It is not terribly well known, and I only ran into it because my high school put on a production several years ago.

The play is a comedy with tragic elements, or perhaps a tragedy with a comic streak. It takes place in 1654 at the court of a French prince. The main characters are a troupe of actors led by one Elomire, their patron the prince, and a troubadour named Valere. Elomire is a serious actor, who believes that plays are art and should be treated with respect; Valere plays to the common element, and cares only for the laughter of his audience. The play centers around the conflict between serious art and cheap comedy, as Elomire loses his position, his patron, and his troupe to Valere's slapstick routines.

Although the play is well-written and balances the audience between sympathy for the noble but lost Elomire and enjoyment of Valere's comedy, the plot is not its most unusual feature. The entire two-hour show is written in ten-syllable rhyming couplets, except for one twenty-line epilogue. This includes monologues, dialogs, and even several conversations with several people speaking at once, in rhythm. This is very difficult to do when acting, but the end result can be truly spectacular.

The effect is difficult to describe, so here's a quote. This is Elomire attempting to explain to his troupe why Valere should be shown the door. It's also a quite nice summation of American government today, but that's just my political side showing.
(Yes, I'm skipping a line at the beginning, so there's a rhyme missing.)

"Our lives are governed by such foolish men
And we're to blame because, misguidedly,
We hold to the belief that it would be
More difficult to keep a fool at bay
Than simply just to ... let him have his way
At first this seems a harmless compromise
But hot air has the tendency to rise
Until it finally overwhelms your life!
That's when a fool will really twist the knife -
When he gets power! And he always does!
Then grit your teeth and swallow hard because
He'll mock you every day with your mistake
Of underestimating what a snake
A fool can be if given half a chance!
He'll treat you like the footman at a dance
And revel with Mephistophelean glee
In how his presence shall, eternally
Evoke, with sharp refrains of ridicule,
The cutting truth that you've been made the fool!"