Double art history
The classroom rules start before we've even left the box office.
"Line up, and follow me, crocodile-style so I can make sure you are all safely across the road," says the steward cheerily.
The mainly grey-haired audience giggle.
We are back in school for a performance called Double Art History - literally behind desks in a classroom in Edinburgh University.
The premise of the show is that the school's regular art teacher has suffered a nervous breakdown and a supply teacher has arrived to give the class its final push for a history of art exam.
Its star Will Gompertz isn't a stand-up but a respected director of the Tate Gallery in London.
He went to comedy classes to boost his public speaking skills for lectures and decided to go the whole hog and put on a show at the Fringe.
It's not so much a show as a swift lecture on modern art, 27 art movement "isms" dispatched in less than an hour.
But there's plenty of humour - from the drawings of human body parts we all have to do when we first sit down - leading to icebreaking comments like "madam, could you show me your husband's penis?" to the silly hats and props which become an aide memoire for the various art movements through the whistle-stop tour.
From impressionism to post-impressionism to primitism, orphism, automatism and fluxus, he races through them all with slides of the artists and the artists involved.
Dadaism provokes the nearest Gompertz gets to a heckle.
His explanation that the movement, as championed by Duchamps and his urinal exhibit, changed the face of modern art forever by suggesting any everyday object could be art - since it was the concept, not the final artwork that mattered.
A man in the front row furrows his brow and raises his hand.
"But how do we know that it's a work of art, and not just someone having a joke at the art world's expense," he says.
"A very good question," says Gompertz, with barely a pause,"come and see me after class."
And there is genuinely a test at the end - 10 questions on the isms - which most of the class pass with flying colours (having muddled our fauvism with our cubism, we lagged slightly with 80%) before the class is dismissed and we leave, not just entertained, but genuinely having learned something new about modern art.
Double Art History is at Underbelly's Hullaballoo at 1750 BST.