Ask HN: What were the most interesting workshops you participated in?

Hi everyone.

I'm doing a little research. I'm part of a modest initiative in Andalucia (Spain) to organize some workshops in my city during the next months and I would like to suggest some of them related not only to technology (software and hardware) but also relating to DIY, science, art, crafting, startups, businesses... so what were the most interesting workshops you participated in?... and why were those workshops so interesting?

Our intention is to attract people of all ages to the sake of knowledge and the creative and entrepreneurial spirit.

Thank you in advance!