New comedy club in Belfast's Loft – artist's studio by day, platform for new comedy talent by night – is much more than a cheap and cheerful night out

If you want an evening out which is like no other in Belfast then I recommend Voicebox. You will find it four storeys up in a space that is a painter’s studio by day, and where half finished canvases leer down at you from every angle. Wooden support struts lattice the roof: the venue is Loft by name and loft by nature. There is no bar, no stage and nobody tells any jokes.

Nevertheless, Voicebox is the most refreshing, involved and inventive comedy night in town. It takes complete advantage of the rough hewn nature of the space, and the fact that the audience, seated on scatter cushions, are a part of the performance. The sheer scope of invention on display here (tonight and every month) makes your standard comedy gig – featuring hacks in t-shirts telling implausible and off-colour jokes – seem lazy and unambitious, blinkered to the possibilities of comic form. I should also stress at this point that Voicebox is also extremely funny.

I laugh a lot. And, crucially, there is none of stomach-knotting horror that a dying act induces, none of the ritual humiliation that comes with audience baiting. The lack of a stage, the lack of an obvious separation between performer and punter, lends the evening a convivial, conversational quality – the mood is light, the laughter easy. The atmosphere is less like a bear pit than the ball pit in your local crèche. It’s fun.

It is also a place where comedians can try out different things. Host, Marcus Keeley, is known in Norwich, Paris and Belfast for his post-Dadaist multi-media performances, but here he is every inch the congenial host and, dare I say it, slick? He lulls us into a false sense of security until he is stopped in his tracks by hectoring jobs-worth, Christopher Goodfellow, an agent of Governmental Approved Comedy, who hands him a stack of bumf to fill in in triplicate.

Aaron Marshall is horrifically believable as the uncivil servant, meaning he will probably not be cast in the next series of BBC Northern Ireland's newest 'comedy' series, Number 2s. Goodfellow appears periodically throughout the evening, becoming more inebriated and fuelled by jealously and impotent rage as the night wears on.

Anne-Marie Mullan is first up and assays the first and possibly only topical gag of the evening: 'I dressed as Maggie Gyllenhaal in Secretary, because not every film about BDSM has to be as bad as Fifty Shades of Grey, but I realised I just look like Helga from Allo Allo.' She pauses for dramatic effect. 'This is what a Femenazi looks like.'

Bobby Best thereafter inducts us all into The Church of Optimus Prime, of which he is an ipsissimus. 'This is a real dog collar. Don’t ask me what I had to do to get it!'

Monk–fish the detective then bursts onto the crime scene and goes about interrogating the audience in his piping Sarah Millican brogue. ('The whole show is filmed under-water for my comfort.') No one is above suspicion as he turns on the audience to bamboozle them with his Rorschach cards: 'What does that look like to you?' 'Er, a bat.' 'No, it’s Paul Ross: national treasure and the better brother. What about that?' 'A crow.' 'Ah, that’s right. I know him. That’s Kevin.' It’s a masterful turn from Ruaidhri Ward, the man behind the fish face. Even his asides are hilarious. 'I walk like Beyonce to let everyone know I’m in control.'

Adam Laughlin, Derry’s beardiest man – 'woodland animals might leap from it' – appears in the second half of the show and, thankfully, without his ukulele. It's best I’ve seen him before: his style is anecdotal to the point of rambling, but his set pieces – the young Santa impressions or his seeking reparations from the child slave who made his Primark trousers when the zip broke – are sardonic and well observed.

Peter Davidson’s turn as Skeletor, supping Southern comfort from the bottle and listing a string of grievances against Adam of Eternia, is another highlight. Skeletor reveals what all the old gang have been up to. 'Man-E-Faces had a massive coronary. Shame. Lovely guy.' He also answers a few questions about his heritage. 'The name is Dutch-Irish. I’m of mixed parentage – my father was dead and my mother was a pervert.'

Last on is Ireland’s darkest comedian, Dermot H Dark-Materials, straight out of Monaghan and rocking hard to The Who’s 'The Seeker', in his wrap-around shades, light-bulb cane and Faces of Death jewellery, he looks ready to drop serious truth bombs. He is a backwater Frankie Boyle, a Bill hick. In fact, his status is by default: he came 23rd in a dark comedy competition in Lowestoft, but was the only Irish entry. Really he is a nice boy, forever misunderstood by small-town authority figures. Even his teachers suspect him of being a Satanist because of his Spiderman medallion...

Voicebox is a cheap and cheerful night out. Ordinarily that would imply that it is a bog-standard diversion, but the sheer level of invention thrown up by each Voicebox event is truly inspiring, as is each contributor’s bravery and commitment to moving on to something new each time. That would be my only complaint, in fact. I’d like to see some of these characters come back again.