Optimo 20 – curated by DJ duo JD Twitch and JG Wilkes, otherwise known as Optimo – goes against conventional wisdom regarding music events: get the names, bring the crowds. None of today’s acts could be classified as “names”. In fact, it’s tough to describe the smorgasbord of music at the Galvanizer’s Yard today in any unifying way. But that’s surely the point.

Today’s event celebrates the 20th birthday of Optimo (Espacio), a legendary underground club night in Glasgow’s Sub Club running every Sunday from 1997 to 2010, and Optimo 20 is crafted in its graven image. 19 acts spanning numerous genres, geographies and generations are to play across three stages, and there’s surely something catered to everyone’s tastes (as long as those tastes remotely orbit avant garde and dance music.)

The anteroom to the action is kitted out like a chill-out space-cum-miniature art exhibition: vintage television footage of Serge Gainsbourg is projected on a wall, and posters, t-shirts and tote bags read “I’m there”, a “living in the moment” ethos kindly echoed in anti-camera phone notices scattered about the venue. Suddenly the Optimo guys’ suspicion towards reviewers is understandable; if anyone at the party is a stick in the mud, it’s likely to be the stiff with the camera, or a notebook and pen.

Far from being a hostile environment to social media devotees and humbled critics, the venue is as warm and welcoming as the people within. “I WANNA SEE ALL MY FRIENDS AT ONCE” reads an enormous screen in the Galvanizers Yard, in reference to the 1982 single Go Bang! by Dinosaur L (more commonly known as one Arthur Russell), but also as a rallying cry for the metaphysical totality of having a fucking good time.

Glasgow DJs Sofey and Ribeka warm up the crowd respectively in the dance-nook Poetry Club and the TV Studio, as the first live act of the day gears up. Finnish producer/musician/DJ Timo Kaukolampi delivers cosmic electronica that nicely works up a steadily-filling room with hypnotic rhythms and unexpected left-turns that hurt like a wake-up slap to the face. Dark and thumping, it’s nevertheless gentler than the abrasive and infectious drum-and-electronics EBM of his other project, the cloak-donning K-X-P, which draws crowds later on in the day.

As tender counterpoint to the hissing dynamism of other acts today, Australian musician Carla Dal Forno delivers a risky set of misty Badalamenti-infused pop, fittingly bathed in cold, blue light. Dal Forno’s downy vocal is in constant peril of becoming buried under nebulous ambience and unruly feedback, but a balance is struck, and the whole performance hangs together as well as a tastefully-lit fresco.

Just when the festival seems liable to take a fairly predictable electroclash/industrial/synthpop turn, left-field choice Nurse With Wound dispel any notions that Optimo aren’t still capable of subverting expectations. Britain’s premier avant garde heritage act are the subject of much speculation ahead of their set – and anticipation mounts with the perennial bother of technical difficulties. But Steven Stapleton’s Dadaist troupe don’t disappoint. Nordic incantations boom over the hellish chirping of devil-fowl; indistinct audio files are mangled and bent out of shape by Stapleton’s maniacal turntable exploits; infernal growls escape a bodhrán as if it were a porthole to antediluvian underworlds. NWW invoke a mythical and terrified England that never left the primordial wood; pagan ritual reawakened by European modernism. Mercifully, they perform with the madcap humour of a particularly nihilistic issue of The Beano. Well into the project’s third decade, Stapleton’s primary outlet is as unique, astonishing and brilliant as ever.

As Glasgow’s temperamental weather finally settles into a downpour, nearly flooding the outdoor food stalls, the smokers make their way indoors for the business-casual electroclash of ADULT., a group coincidentally also celebrating 20 years of existence. By the time their set of jagged numbers is up, the audience is lathered up with enough booze for King Ayisoba and the rhythmic intensity of his backing band. Kologo-led jams tighten and slacken like a living beast, as King Ayisoba’s robust voice flips from furious yelling to sharp bleats. It’s a welcome change from cold industrialism, and surely the best dance music of the day.

Meanwhile, over at the heaving Galvanizers, the crowning moment of Optimo 20 happens as eminent DJ The Black Madonna goes back to back with the men of the hour Optimo. Both parties are harbingers of big tunes in two distinct cadences; Black Madonna’s sylphic disco ascends to heaven, while Optimo’s impish sound contains shades of darkness. Combined, the effect is positively transcendent. When Optimo’s JD Twitch first takes to the decks, his perpetually-furrowed brow lifts with joy as dancers cheer and applaud the achievements of Optimo over these last two decades.

This spirited coda is a reminder of exactly what today’s celebrations are for; those Sundays at Sub Club, now a distant memory to some and a folkloric point of origin for others, moved to the strange rhythms of genius outsiders. Optimo 20’s musical diversity – house, avant garde, EBM, synthpop, traditional Ghanaian kologo music – is far from chaotic curation; it’s bound by a community. Optimo 20 is testimony to what the Optimo crew have said all along: do it for the music, do it for each other, or don’t do it at all. A neon sign in the art exhibit reads “we love your ears”; may Optimo love them for two decades more.