The Unbelievable Truth/Funny

"Graeme: And in... Atlanta, Georgia... [audience laughter]
 * 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:

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!"

"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!""
 * 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:

"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."
 * "...Which I think adds to the general picture of Isaac Newton that we're building up, that he was an idiot."
 * Charlie Brooker's list of things supposedly invented by Thomas Edison:

"Henning Wehn: But once all the chickens were barbequed, there were no more eggs, only mass starvation.
 * 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:

David Mitchell [mishearing]: I beg your pardon?!

Mark Watson: He said "mass starvation"! Two separate words!

[Much laughter]

David: That's definitely the biggest laugh mass starvation has ever got!"