‘This is the best gig we’ve ever played! It’s also the first gig we’ve ever played!’

The Arctic Monkeys saw no need to include a lengthy saxophone solo in ‘Do I Wanna Know?’, their slow-burn 2013 rocker with a killer chorus. It’s highly likely no one has ever listened to that song and thought to themselves, “This could be improved with a lot more saxophone”.

But that’s exactly what a group of dapper lads from media agency OMD decided to include in the opening song of their brief set on a drizzly Thursday night in Auckland. As The Pixels, they’d promised to provide as much variety as an op-shop record bin and they delivered, turning the uber-grungy UK guitar anthem into a yacht rock opus.

Onto a good thing, possibly inspired by Kenny G, they then repeated the trick for a similarly jazzed-up cover of MGMT’s ‘Kids’. “You’re a sax offender,” declared one of three impressed judges after their set. Their mustachioed front man grinned like he’d just gotten away with a crime.

At the annual Battle of the Ad Bands, a kind of adults-only Smokefree Rockquest headlined by bands consisting solely of those who work in media or advertising industries, the motto for the night’s ridiculously compelling four-hour show was “anything goes”.

They weren’t kidding. For the first time in three years, those there holding their $50 tickets, or bands who’d paid the $500 entry free, arrived at 6pm ready to party. From the vodka shots and free drinks vouchers being handed out at the door to the homemade signs and rowdy moshpits that formed in the front rows of Galatos throughout the night, everyone got what they came for.

The nine acts playing back-to-back performances were often hilariously exhilarating. Given 15 minutes to play whatever motley medley they pleased, some chose sets full of songs sure to appeal to the night’s judges, supplied by Radio Hauraki, with the Red Hot Chili Peppers and The Killers strong favourites.

Others mixed it up, taking wild swings that could easily have come unstuck. From the local branch of Dentsu, Jille & the Meat Lovers began a ferocious version of Nirvana’s ‘Smells Like Teen Spirit’ then pivoted by mixing in the lyrics to Michael Jackson’s ‘Billie Jean’. Chelsea Parsons, who has the job title “head of success” at her day job at digital marketing company Hype & Dexter, ably rapped the lyrics to Missy Elliott’s ‘Get Your Freak On’ before seguing into De La Soul’s part of Gorillaz’ ‘Feel Good Inc’.

Surely the night’s most diabolical performance came from a band of misfits called AC/DDB. One looked like Ronald McDonald had joined Slipknot, while another resembled the Hamburglar if he grew his hair out and stole a guitar. The bassist had apparently spent three hours backstage bedazzling his dome with fake diamonds.

Fronted by a punk-rock Julius Caesar complete with tomatoes hanging around his groin, the six-piece gave the Venga Boys’ song ‘Boom, Boom, Boom, Boom!!’ a punk-rock makeover, then nailed Black Sabbath’s ‘War Pigs’ and Rage Against the Machine’s ‘Killing in the Name’, receiving the rowdiest response of the night for their efforts.

Between-song banter was also worth applauding. “I’m nearly 50!” yelled The Poster Boy’s singer after ripping through Blink-182’s ‘What’s My Age Again?’ “This is the best gig we’ve ever played! It’s also the first gig we’ve ever played!” yelled the excitable guitarist for Jille & the Meat Lovers.

Sponsored up the wazoo, I occasionally felt like I was stuck inside a chaotic episode of The Price is Right as the night’s over-eager stage host yelled out a string of brand names – “Huffer!” “Prego!” “Coffee Supreme!” “Apex!” – and threw hefty gift packs of Whittaker’s chocolate into the crowd.

Out there, the vibe veered towards a Remuera student house party. Many were there for one thing and one thing only. “There’s another bar upstairs,” yelled one happy drunk, winking at me in the queue at the downstairs bar. “Time to get drunk!” yelled one singer after shimmering her way through the Sugababes’ ‘Overload’.

But the soundtrack to all this chaos was taken surprisingly seriously. Bands, some who’d formed over the past few weeks, others that have been playing together and performing at BOTAB for much of its 13-year existence, had practised for the occasion far more than they’d probably like to admit.

Only occasionally did the wheels feel like they might be falling off. Inviting a cross-dresser on stage to perform during Shania Twain’s ‘Man! I Feel Like a Woman’ felt out of touch, and it wasn’t the only time someone appeared in drag on the night. No one seemed to catch the irony of a room full of advertising execs chanting, “Fuck you / I won’t do what you tell me,” when it’s their exact job to get people to do exactly what they tell them to.

The industry’s not known for lacking self-confidence, or for having an over-abundance of self-awareness, and you could read the night as a drunken celebration of the arrogance, ego and showboating that permeates the craft. But you couldn’t fault the commitment of everyone involved determined to live out their rock-star fantasies in 15-minute chunks.

I spent most of the night with my mouth open, either shocked by what was happening, or laughing at their increasingly shameless antics. Perhaps it’s no surprise that the night’s winning act DayLit (a quick admission: I work alongside most of those in the band, which consists of members of The Spinoff and the Daylight creative agency) did so by taking things down a notch or two.

Rather than performing out to the crowd, their Polyphonic Spree-style takeover of the same stage Dave Grohl once played on invited onlookers inside their performance. Opening with a cover of The Beatles’ ‘Come Together,’ they appeared to be playing for each other as much as those in the audience. Their carefully constructed set built in energy and speed, swapped from male to female vocalists for Blondie’s ‘Heart of Glass’ then erupting with a finale of The Beastie Boys’ ‘Sabotage’.

It was another wild swing on a night full of them, but their lack of costumes and humble winning celebrations played well against the over-the-top antics of most other acts on show. “I would pay to watch that set,” said one judge afterwards. Most of those in the crowd were too drunk to take much of anything on board, but perhaps there’s a lesson for the advertising industry to learn in there somewhere.