For anyone with even a passing acquaintance with the internet, Mark Grist is the teacher who taunted a 17-year-old rapper with the line: "You wank off in sandals to pictures of Gandalf."
The YouTube video of the rap battle between English teacher Mr Grist and teenage rapper Blizzard has been viewed almost two-and-a-half million times since it first aired in December. Mr Grist's machine-gun volley of smartly lewd insults made him an instant viral star.
Now, in Mark Grist: Rogue Teacher, a one-man show at the Edinburgh Festival Fringe, Mr Grist is examining - comically, poetically - what it means to be an online sensation.
"For a month, it was just crazy bombardment," he said. "It's a bit like being part of Fight Club - random people start looking at you funnily. It's a bit weird. You're just a guy who was an English teacher.
"But I think a lot of people like teachers who are a bit off the wall. So a lot of these guys feel as if I'm their teacher, or feel that affinity that they would have with their own teachers who do crazy stuff."
Mr Grist taught English at Peterborough's Hampton College for five years: "When I was younger, I always wanted to be either a rock star or a teacher. I tried being in a band, and we were rubbish." However, he was rapidly promoted to head of year, taking him away from the classroom teaching he loved. He now works as a supply teacher in addition to producing poetry.
Although Mr Grist admitted that much of his own rap-attack was "questionable" (Blizzard's mother comes out of it rather badly), it was Blizzard who was mocked by the press as a cocky teenager. "He was rap battling," Mr Grist said. "If ever there's a place where it's OK to be a cocky teenager, it's a rap battle.
"He's actually a very good lyricist. And I'm manipulating the crowd a lot. There's a lot of classroom-teacher stuff that I'm using. I had to run an assembly every week: I'm used to having a room's attention and holding it. That was invaluable."
Mark Cooper-Jones, too, is demonstrating the transferable nature of classroom skills in Edinburgh this year. The geography teacher at Blackheath High, in southeast London, is staging a show about what it means to be one of his breed.
"I think the very idea of being a geography teacher is inherently amusing," he said. "They're usually this weird creature: bearded, with elbow patches. Almost the paradigm of teachers, for some reason."
He insisted that the stories he tells during the show are absolutely true. There is, for example, the boy who set off a firework during a lesson and claimed he was simulating a volcanic eruption. There is the primary child who said: "An egg is cold, like the sun." And, like all good geography lessons, the show concludes with a countries and capitals quiz.
In fact, learning while you laugh is a surprisingly popular activity among festival-goers, according to James Lowey, producer-director of School Night. Presided over by a "form tutor" compere, School Night asks comedians to deliver lessons in their favourite subjects.
"Lots of comedians are very geeky about specific things," Mr Lowey said. "And people do tend to feel very fond about school. We've had people turn up in school uniform."
Such oversized pupils have a distinct advantage over the real thing: there is no chance of seeing them in school on Monday morning.
While his pupils have not seen his current show, Mr Cooper-Jones did invite them to a sketch show in which he pranced around in his boxer shorts, pretending to be a bird of paradise. "I came up afterwards and said: `We never talk of this again,'" he commented. "Amazingly, they haven't."
SCHOOL DAZE: EDUCATION ON THE FRINGE
Mark Grist: Rogue Teacher
Teacher turned rap-battler on pupils and pentameter.
Mark Cooper-Jones: Geography Teacher
Emphatically reinforcing geography-teacher stereotypes.
Alternative Sex Education
Burlesque performers share stories of classroom awkwardness, BDSM and whips.
A Midsummer Night's Dream
Magic, fairies and a donkey's head, performed by St Marylebone CE School.
Comedians teach their chosen subjects.
For the Love of Willie
City of London Freemen's School, in a play about a girl who has a brief affair with her employer.
North London Collegiate School tells the true story of a three-year-old left alone in her mother's car.
Back to School
Interactive comedy, in which the audience takes classes in drawing and dissection, eats school dinners, runs in the playground and pets the school hamster.
Photo: English teacher Mark Grist won a `rap battle' and became an internet sensation
Original headline: If you dig the rapping Sir, get to his gig in Edinburgh