Their lunchtime theatre, A Play, A Pie and A Pint, has been running for 10 years, producing new plays, cheeky pantos and old classics, all served up with a trusty Scotch pie - although quiche is available for those of the vegetable persuasion.
And they didn't name it A Play, A Pie and A Pint (PPP) just for the alliteration. They could have opted for A Performance, A Prosciutto and a Pinot Noir, but those pies and pints were chosen to make a statement: this is cosy, welcoming theatre, with all pretensions cut away.
Alan Bissett, who has written for PPP, says 'people have this idea that theatre is a bit poncey or posh, so when you emphasise a pint and pies as part of the experience you tell the audience there's nothing to be afraid of, that it's more like the experience of going to a football match, and in Glasgow that's a very important message!'
It offers a relaxed and informal way to access theatre, although the actor and writer Dave Anderson accepts that theatre is still seen as something for the middle classes. 'It's a shame but it is, in the main, an elite activity. But here it isn't,' he says and gestures round the warm interior of Oran Mor's Whisky Bar. 'Theatre here is very welcoming. It's user-friendly. And - it's in a pub!'
Sarah MacFarlane, PPP's Assistant Producer, agrees they're keen to shrug off the exclusive image of theatre. When she was persuading friends to visit they fretted about the dress code. Sarah laughed and told them 'you'll be perched on a seat eating a pie!'
There is indeed etiquette to be followed at Oran Mor's theatre but it has little to do with genteel behaviour. Sarah says 'when the doors open it's get down there, get straight to a seat, get your bag and jacket down then go up and get your pie. You learn the routine!'
But there's no need to fear any hungry Glaswegians more concerned with their dinner than the show. Joe Douglas, director of PPP's current play, The Call Of The Wild, says 'I think you can gauge how successful the show is by how noisy the cutlery is. If they're taken with something, they forget about the pies.'
And even though, after ten years, the pies remain the same, the plays never are.
By the end of the year, PPP will have produced 351 new plays and that isn't counting their revivals of old favourites, known as Classic Cuts. 'There's a new show every single week,' says Sarah 'so the audience know if they come and it's not up their street they can come back next week and it'll be something totally new. Some folk don't even look at the program. What's the play today, they'll say. Who's on? They embrace the diversity.'
Two of Glasgow's up and coming playwrights, Tom Brogan and Karen Barclay, welcome that PPP tries to reach ordinary people on their lunchbreak who might otherwise never set foot in a theatre. 'Many people aren't sure if theatre is aimed at them,' says Karen. 'In the 1950s it was very intellectual, then it turned commercial with big musicals and plays with stars in them. Then there was subsidised theatre which people often see as 'arty''. But PPP is clear about what it offers the Glasgow public and that's where its strength lies.
Tom Brogan agrees. 'I went to see Des Dillon's Singing I'm No A Billy He's A Tim and it was packed because the people knew what they were getting: a football-based banter comedy. It'll be the same with Still Game at the Hydro. People know what they're getting.'
This clarity about what's on offer helps deflate any sense of initimidation the theatre may hold for a newcomer. You might wonder where do I sit? Is there a dress code? Will people tut at me if I sneeze?
Karen remembers how nervous she was when she first visited Glasgow's Theatre Royal and admits it can be scary, especially when you consider Harold Pinter. 'He didn't like people coughing during his show and saw it as an act of aggression but sometimes you just need to cough!'
But you can't please everyone. Tom admits he gets annoyed, not at the folk who cough, but at those who turn to glare at the splutterers. That haughtiness - which you don't see at football matches or the cinema - bothers him.
Karen feels theatre's formidable image could be eased if plays were still shown on TV, as with the BBC's old Play For Today. These fell out of favour, she says, as they began to be seen as preachy or pompous and TV started to demand glamour instead of ideology.
But TV does have a role to play in promoting theatre. Dave Anderson points out that Mrs Brown's Boys began life at the Pavilion, and now we have Still Game being brought to the stage, so the crossover is there to be exploited. But he says TV can be no substitute for live theatre. 'People don't watch TV in big groups,' he says 'but theatre is a social event. That's what makes it different from TV. You're all there at the same time. It's a shared experience.'
So, with this egalitarian theatrical crusade going on, is Glasgow still overshadowed by Edinburgh?
Alan Bissett says no. 'Glasgow is now a great theatre city that creates its own scene, rather than relying heavily on importing it. PPP is very much the engine room at the heart of that.'
Lauren Humphreys of the Glasgow Theatre Blog agrees passionately, saying Edinburgh seems to concentrate now on big commercial productions but 'the focus in Glasgow is much more on innovation and risk-taking. There's actually more of a 'fringe' spirit throughout the year in Glasgow, with the most original and unlikely venues staging theatrical productions.'
So Glasgow theatre shines brightly all on its own, and PPP is at its brave centre, sending some of its plays all over the world. They've left Oran Mor to be produced in New York, Turkey, Brazil, Tasmania and Pamplona - but they all started right here, on Byres Road.
A Play, A Pie and A Pint is on BBC2 on Friday, 13th June