Greg Pickhaver, Charli Robinson and Brad McEwan in It's a Knockout. At 63, the revered sports commentator's alter ego, Greg Pickhaver, is just as enthusiastic. Recently returned from Malaysia - where filming for Ten's rebooting of game show It's a Knockout was completed in five long and humid nights - he is a ball of energy. ''I loved it,'' Pickhaver says. ''A tremendous experience that now feels like a weird dream.'' Today, though, Nelson is doing the talking. Before the boxing play-acting starts, he sits in a tiny dressing room extolling the virtues of hosting a program he dubs the ''people's Olympics''. ''People do love It's a Knockout in a way which is a bit hard to understand,'' he says. ''But, one day, everyone turns 11, that's the only way I can explain it.

''This is an extremely interesting show for a certain age group and it sticks in their minds. ''It's, 'Look at these adults, they're doing the most ridiculous things. Isn't it funny?' And it is. It's pure slapstick.'' Some would view It's a Knockout - which he co-hosts with sports presenter Brad McEwan and former Hi-5 star Charli Robinson - as an odd career choice for Nelson. He and co-commentator ''Rampaging'' Roy Slaven (John Doyle) have been delivering their comic observations for nearly three decades. The long-running double act found fame on satirical sports show This Sporting Life on Triple J from 1986. Along with memorable live calls of AFL and NRL games and various TV shows, it is The Dream with Roy and HG, their nightly TV round-up of the Sydney 2000, Salt Lake 2002 and Athens 2004 Olympics, that stand out. So why would Nelson, without Slaven, want to join a rebooted 1980s game-show format? ''It's an opportunity to do what we do best,'' he says. ''Both Roy and I consider ourselves commentators and these are games that no-one's ever seen before.

''Ignorance is bliss and when you go along you see people behaving and doing really - I'm not talking about really, I'm talking about extremely - stupid things. It's on par with the gymnastics or the synchronised swimming.'' Nelson, whose radio stint at Triple M with Slaven is soon to finish, says he has been ''in training'' for the show while hosting TV comedy improvisation program Comedy Slapdown and ABC TV poetry contest Bush Slam. ''So I feel like it's been a logical progression over many years to this point,'' he says. Inspired by the French program Intervilles, It's a Knockout first appeared on BBC1 where it ran for 22 years. Other British networks took it on between 1990 and 2001 with various adaptations popping up on US, New Zealand and Australian TV. Comically daggy to contemporary eyes, the Australian It's a Knockout, which ran on Ten from 1985 to 1987, featured contestants dressed as giant peanuts, penguins, martians and doughnuts undertaking bizarre athletic obstacle courses in a field in Dural. Hosts Fiona MacDonald and Billy J. Smith - dressed in costumes mimicking America's Wild West, ballroom dancers or 18th-century royalty - cheered on state teams, each competing for charities. Little has changed. To save money, the show's modern-day incarnation - with production costs partly funded by McDonald's Australia - was filmed in Kuala Lumpur on a purpose-built set, also used by other countries filming their adaptations of the show. ''The week before we came to film, they had the German version working there,'' Nelson says. The 2011 incarnation features 24 games with players dressing as giant ostriches, giraffes, bottles, frogs, electric wall plugs, sumo wrestlers and mums pushing players dressed as babies in supermarket trollies.

Competing for the Billy J. Smith Cup, teams build bridges, run on conveyor belts, push pies into faces, catapult enormous rubber pancakes over walls and evade fake wolves to scavenge carrots. ''Rat a Tat Tat is my favourite,'' Nelson says. ''It's women dressed as rats inside bubbles with large pieces of cheese. They roll down a ramp, hit a swimming pool, paddle across the pool, get out of the pool, drop down on the studio floor and then, still inside the bubble, roll on to the up ramp to the twin turntables of terror.'' As an exercise in commentating, Nelson says he was rarely lost for words during the filming. Hearing him laud the Turntables of Terror or, for one other game, the Duelling Disks of Doom, conjures memories of his and Slaven's commentary. Nelson looks back on the whole experience with a degree of amazement. It was, he says, the hardest working experience of his life.

The program's set, built in a skate park with a roof and no walls, required reliable lighting so filming began at 5pm and finished about 5am. ''I knew what I was getting into but I never prepared to be up all night,'' Nelson says. But he remains charmed by It's a Knockout, mainly because it counters most game shows on TV now. ''The contestants who do this, I don't mean to be unkind to them - they're extremely generous, that's their main thing - but they don't bring many skills to it,'' he says. ''They're not cooks, they don't have an act that sings, they don't plate-juggle, they can't do the Pride of Erin. They just get out there and blast away. And, in the current climate of television, there's something quite nice about that.'' It's A Knockout airs Sunday on Ten.