That was the challenge set to readers of the Radio Times last year. They responded in their thousands and the top brass of the industry has now drawn up a shortlist of the great moments in television history.
Next weekend at the Edinburgh International Television Festival, Britain's most senior television executives will unveil their choices of the best drama, current events and comedy - not of the year, nor the decade, but since television began.
The festival executive committee, some of the biggest names behind the scenes of British television, produced the shortlists. Peter Salmon, controller of BBC1 and his opposite number on BBC2, Jane Root, sat alongside ITV's controller of drama, Nick Elliott, Stuart Cosgrove of Channel 4 and colleagues from Channel 5, Sky and the independent sector to choose the top 10 moments in each category. David Frost will present his own choice at the festival.
"Comedy was easiest, news the most difficult and drama the most contentious," admitted Lis Howell, senior vice president of Flextech Channels, a pay television operator.
They have shortlisted the Queen's coronation in 1953 as well as a double bill of Diana, Princess of Wales, with her Panorama interview ("There were three people in this marriage"), followed by her funeral two years later.
The Moon landing of 1969 appears, as does the release of Nelson Mandela from his years of imprisonment nine years ago. The collapse of communism is marked by the fall of the Berlin Wall and there is a place for Michael Buerk's moving report from famine-stricken Ethiopia, when he told millions of stunned viewers "this is the closest thing to hell on Earth".
Sport is represented by England's victory in the 1966 World Cup final and there is a place for Richard Nixon telling the American public there was "no whitewash in the White House".
The drama section is heavily influenced by soaps, with listings for Coronation Street's Ken and Deirdre and the body under the patio scene from Brookside. And there is a listing for the episode of EastEnders on Christmas Day 1986, when Dirty Den served Angie with divorce papers. The choices in comedy are a raft of British favourites: Monty Python, Fawlty Towers, Dad's Army and Tony Hancock.
The shortlists themselves were condemned last night by Professor Richard Hoggart, the broadcasting and literacy commentator. "It's a mirror of popular taste," he said. "It's like saying that the best newspaper today is the Sun."
Long lists were drawn up from programmes chosen by readers of the Radio Times for its 75th anniversary last year, supplemented by suggestions from the magazine and others in broadcasting.
Personally, Ms Howell was somewhat shocked at the absence of those triumphs of British drama: Jewel in the Crown and Brideshead Revisited. She also lamented the absence of the death of Minnie Caldwell on Coronation Street. "It was the first death in a soap opera," she said. Nonetheless, her cries of horror as omissions were pointed out confirmed what she herself observed: "Whatever you do is wrong."
Richard Hoggart, who wrote The Uses of Literacy and the Pilkington Report on broadcasting in 1962, said he could understand some of the choices. The rape of Irene Forsyte was striking "because it was early to show that kind thing. Nowadays it wouldn't matter at all".
The Princess of Wales's interview on Panorama had been "an eye-opener", although her funeral was "wedding cake stuff". The fall of the Berlin Wall and Nixon's Watergate address "almost go without saying".
But Professor Hoggart condemned many of the decisions as clear evidence of bad taste, adding: "I would have thought one of the most memorable moments on television was [Singing Detective writer] Dennis Potter's final interview with Melvyn Bragg."
However, Lis Howell refused to accept that populism was necessarily a bad thing. "The committee is professional. People like Nick Elliott make drama across the board for a large audience. There's got to be a certain amount of subjectivity. But these should be ordinary people's views of what were the best moments."
The death of JFK was excluded on technical grounds, because the amateur footage which has become so well known emerged later and the news coverage itself was not "particularly good".
And as Ms Howell pointed out, it was moments, not whole programmes, that counted in this poll. The winners have been chosen in a further poll of Radio Times readers and will be announced next Saturday by Ulrika Jonsson.
"What we're talking about is those defining, epiphany-like moments," Ms Howell said. "Things like the coronation of the Queen were the first time a lot of people saw television. My grandma got her television for the coronation."
As for the omission of one of the biggest critical and popular hits of recent times, Pride and Prejudice, Ms Howell noted: "You've got to remember we're looking at 50 years of television, which is why Jennifer Ehle's boobs may not have made it."
Ken discovers Deirdre's affair. Coronation Street 28.2.83.
Mrs Peel springs into action in black catsuit. The Avengers 28.9.65.
Sinbad unearths the body under the patio. Brookside 18.9.93.
Quentin Crisp flirting with sailors. The Naked Civil Servant 17.12.75.
Yosser Hughes "gissa job". Boys from the Blackstuff. 31.10.82.
The rape of Irene Forsyte. The Forsyte Saga 11.2.67.
Who shot JR? Dallas 26.5.80.
Cathy's kids are taken from her. Cathy Come Home 16.1.66.
Happy Christmas Angie. EastEnders 25.12. 86.
"Exterminate! Exterminate!" Doctor Who 21.12.63.
"There were three people in this marriage." Diana, Princess of Wales, Panorama 20.11.95.
"No whitewash in the White House." Nixon addresses the public 30.4.73.
Fall of Berlin Wall. Collapse of Communism in Europe 8.11. 89.
"The closest thing to hell on Earth." Michael Buerk in Ethiopia 17.7.84.
Challenger explosion 29.1.86.
Release of Nelson Mandela 11.2.90.
"They think it's all over ... it is now." World Cup final 30.7.66.
"Mummy." The funeral of Diana, Princess of Wales 6.9.97.
"One giant leap for mankind." The moon landing 20.7.69.
The coronation of Queen Elizabeth II 20.6.53.
"Don't mention the war." Fawlty Towers 24.10.75.
Angela Rippon with Eric and Ernie. Morecambe and Wise 25.12.77.
Del Boy falls through the bar. Only Fools and Horses 8.1.89.
"Don't tell him, Pike!" Dad's Army 31.10.73.
Blackadder goes over the top. Blackadder Goes Forth 2.11.89.
The Parrot Sketch. Monty Python's Flying Circus 7.12.69.
Emu attacks Parky. Parkinson 27.11.76.
"A pint? That's nearly an armful!" Hancock, The Blood Donor 23.6.61.
Pete 'n' Dud: "Bloody Greta Garbo!" Not Only ... But Also 23.11.65.
Edina falls into the flowerbed. Absolutely Fabulous 12.11.92.Reuse content