A comic play by Aristophanes, featuring a very distorted caricature of Socrates as a sophist who fills young mens' heads with airy nonsense and teaches them the rhetoric to make Wrong vanquish Right. It is one of three extended contemporary portraits of Socrates, but is quite at odds with the other two, those of Plato and Xenophon. But as Socrates was a native Athenian, so always around, and was strikingly ugly, he made a very visible target in a play.

Strepsiades is a farmer deeply in debt, largely because of his lazy no-good son Pheidippides, who is mad on horses. Strepsiades wants to send him to enrol in the nearby Phrontistery ('Thinkery'), to learn about the two arguments Right and Wrong, so that he will be able to argue his father's creditors out of their money. The son refusing in horror at being confined indoors, Strepsiades himself resolve to try.

A student admitting him to the Phrontistery solemnly tells him of the useful scientific thoughts Socrates has had, such as how far a flea can jump, and shows him other students intensely scrutinizing the ground; one is so hunched down in study that his arsehole is being trained independently to do astronomy.

Socrates appears out of the sky, where he had been making observations, and tells him they now worship new gods, the Clouds. (They are the chorus of the play.) He explains how they fill philosophers' heads, and also fulfil all the functions normally attributed to Zeus.

Aristophanes' original production of The Clouds came third (last place) in the festival in 423 BCE, and at this point the revised version has an extended complaint about this and a rubbishing of other people's cliché'd plays, with a plea for a better vote this time.

Strepsiades is a hopeless student, but is made to absorb a bit of confused nonsense, and brings his son along to learn the argument between Right and Wrong. He does, but uses it to justify beating his father up.

The Greek name for it is Nephelai; it used to be often known by its Latin name Nubes.