The group gathered in the rain outside a Manchester conference centre was a mixed one: from bearded metalheads to women in cheery, hand-knitted sweaters, they had come not just from the UK but places as far-flung as Sweden, Germany and the Middle East.
But the vast majority of the 360-strong crowd had one thing in common - they were teachers giving up their Saturday to participate in the UK's first mass lesson on how to use the Raspberry Pi, the credit-card sized PC that has been developed to support computer science in schools.
The event was organised by ICT teacher Alan O'Donohoe, from Our Lady's Catholic High School in Preston, who is the founder of the global Raspberry Jam network.
Since he established the first group in Lancashire just eight months ago, more than 80 groups have sprung up across the world - with some as far afield as Istanbul, Tokyo and California.
It may not look flash, but unlike popular consumer technology such as smartphones and tablets, the Pi offers a challenge, according to Mr O'Donohoe.
"People take it out of the box and have to work out what to do with it. Its diminutive size and the fact that it's only pound;20 mean you can put it in all sorts of places where you couldn't put a pound;400 computer - in a bird box, up a tree to record the movements of squirrels - giving it amazing potential to inspire and enthuse children," he said.
The Pi was launched last year by the Raspberry Pi Foundation, a British charity, and has been praised by education secretary Michael Gove, who described it as a "great example of the cutting edge of education technology" that will help thousands of children to develop programming skills.
But its growing popularity comes at a time of flux for computing in schools. The old ICT curriculum has been dropped ahead of the introduction of new qualifications in computer science. The latest draft of the new primary curriculum suggests that even children between the ages of 5 and 7 should "understand what algorithms are [and] how they are implemented as programs on digital devices".
While many teachers have welcomed the scrapping of the ICT curriculum, there are concerns about a lack of expertise in the profession. According to research published by the Royal Society last year, only a third of ICT teachers have qualifications considered relevant to their subject by the Department for Education. Meanwhile, as TES reported last month, recruitment to initial teacher training courses in computer science has fallen significantly.
Rebecca Kelly, a teacher at Shuttleworth College in Burnley, came to the Pi event to find out more. "While we are delighted to be moving away from spreadsheets and Word documents, there is a real fear that some ICT teachers just don't have the right subject knowledge," she said.
"The Pi is an opportunity for a low-cost, back-to-basics approach that will really motivate students."
Graeme Hadwin, assistant headteacher at St Silas CE Primary in Blackburn, was learning how to program a computer game. "I'm just a big kid, really," he said.
"[But] at my school, we've got kids as young as 7 doing simple programming outside of school. I really want to understand how this can be used in a primary setting."