The end of series 4 episode 6. Tony Hawks had spent the entire episode buzzing in on any fact related to America, and had been wrong every time. Graeme Garden, the fourth speaker, deliberately hammed up every mention of American cities and states in his lecture on the telephone, and Tony had buzzed in incorrectly every single time, until at the end of Graeme's lecture, the following exchange took place:
Graeme: And in... Atlanta, Georgia... [audience laughter]
Tony: Did you know I was booked for this show??
Graeme: ... it is illegal to tie a giraffe to a telephone pole.
Tony: I'm not going for that! [buzzer] Oh, hang on, he is...
David Mitchell: Phill.
Phill Jupitus: I reckon it is!
David: Yeah, you're right, Phill!
[much laughter from audience and panellists, followed by the sound of Tony leaving his chair, causing the laughter to redouble]
David: Tony's, er... [sounds of a piano offstage] Tony's, Tony's left, and he's- he's found a piano. He's playing mournful tunes on the piano - oh, he's come back.
Tony: I don't think Phill will be able to sleep tonight!
Unsurprisingly, Tony finished last with -5 points, while Phill won with +6 points.
Discussing how wrong Isaac Newton was about everything else but gravity in series 5, episode 1:
David Mitchell: Basically it's only a bit of luck that he saw the apple fall and he didn't think, "Ah! That proves ghosts!"
"...Which I think adds to the general picture of Isaac Newton that we're building up, that he was an idiot."
Charlie: He also invented a temporary canoe made of rice paper, an official uniform for wasps, the motorised tie-rack, four types of imaginary candelebra, a machine designed to pick up evidence of the afterlife, a helicopter that worked on gunpowder, the street luge, the cassette single or "casingle", Honey Nut Cornflakes, Metal Mickey, C3-PO, Max Headroom and David Cameron.note Of those, he only actually invented the machine to pick up evidence of the afterlife (correctly picked out by Fred MacAulay) and the helicopter that worked on gunpowder (successfully smuggled by Charlie).
Arthur Smith walking off the show in the last episode of series 7 in a fit of pique over an unawarded point, whereupon David Mitchell, sounding slightly disinterested, noted "Arthur Smith has walked off the show, but fortunately at the point when it no longer mattered!" It then turned out that Arthur had won the show anyway.
The constant quibbling over points in series 1 episode 6, where Graeme Garden gets a point for saying he believes Denmark to be a small country, and later Sandi Toksvig tries to get a point for buzzing in on Dara O'Briain saying "Can you imagine a world without rats?"
The latter becomes even funnier when Sandi says that she can imagine a world without rats, and Dara says "I didn't say "Sandi cannot imagine a world without rats"." Sandi says that if he does, she'll challenge...and then Dara continues his lecture with "No you can't."
Series 8 episode 5:
Henning Wehn: But once all the chickens were barbequed, there were no more eggs, only mass starvation.
David Mitchell [mishearing]: I beg your pardon?!
Mark Watson: He said "mass starvation"! Two separate words!
David: That's definitely the biggest laugh mass starvation has ever got!
Henning Wehn abandoning his lecture on computers in Series 10 to give a rant about people impersonating him on Facebook. Arthur Smith gets a point for buzzing in on it.
Henning Wehn: The other thing computers are good for is setting up Facebook pages of second-rate German comedians without their consent. [audience laughter] Meaning they have to spend hours of non-productivity writing to Mark Zuckerberg's criminal money-laundering organisation, with no success at all - apparently, it's fine for anyone to have their identity stolen by some half-wit, and have the breach of the basic human right to your own identity overseen by an unelected, power-hungry entrepreneur, who is unanswerable to the law- [buzzer] -doesn't possess an ounce of common decency- [repeated buzzing] that's exactly what Hitler wanted to do![audience laughter and applause] But I tell you what - but even the Nazi Party wouldn't have had the nerve- [buzzer sounds repeatedly again; Henning's voice is rising in anger] -to steal my identity, and then send me an automated e-mail asking me how satisfied I was with their customer service! [audience applause] David Mitchell: Arthur. Arthur Smith: Well, either Henning is one of the greatest actors in the world, or that is true. Henning: It so is. David: Well, yes, I think you get a point there, Arthur, yes. Arthur: Can I just say, Henning, I thought it was quite a funny idea at the time, and I'm sorry.
Tony Hawks' lecture on gambling in Series 10 leads to a hilarious digression on the notion that only humans kill each other.
David Mitchell: I thought... I thought what some people said - and by "some people", I mean, basically, y'know, hippies - is that- is that, y'know, whereas humans, we have, like, the First World War, animals, they'll- they'll fight a bit for territory, but they won't let it get too far. They won't let it get to actual death. Lucy Porter: But they do eat their own children, David. David: Who do? Tony Hawks: Animals. Lucy: Animals. I've seen it. Hamsters eat their own children. David: That definitely counts as killing each other, eating your own children. Tony: Chimpanzees, I think they murder each other as well. David:(indignant) Well, what have the hippies been saying to me!? Tony: Look, I don't believe that you know any hippies, David! David: Look, I went- I went- I know lots of hippies. Ed Byrne: David thinks I'm a hippie 'cause my hair is long. He doesn't know what a hippie is. He thinks- he thinks Robert Webb is a hippie. Tony: Right, I've forgotten where I was now. David: Robert Webb is a hippie. I mean, for God's sake, he used to have an earring!
In the final episode of series 11, Tony Hawks gets a piano (for part of his lecture on pianos), and hits three different notes, claiming them all to be 'middle C'. Ed Byrne buzzes in and says "Are you kidding?", whereupon it turns out David is relying entirely on Tony to even know if he'd played middle C at all.
In the first episode of series 12, the subject of Ed Byrne's lecture is David Mitchell himself. It goes much as you'd expect it to, and is hilarious from the moment that Mitchell introduces the lecture with obvious trepidation.
David Mitchell: Your subject, Ed, which I should point out here and now is entirely of Ed's own choosing and not one that I have in any way recommended or endorsed, is... me.