I have an opportunity to teach a "studio" for an hour if I want. It can be on anything (not just music), but it has to be an hour, and it has to be participatory. It is voluntary, so it also has to be something people would be interested in. I've played jazz and classical trumpet, and composed instrumental songs, for years.
I've thought about "rhythms of the world" with clapping examples (but I'm not a rhythm expert), getting people to write a 12-bar blues (it would be mostly the lyrics I think), a kind of music appreciation where we listen to why different songs work (people could bring their own songs, but it's not super participatory).
What musical thing would you recommend teaching 10-20 people in a participatory way lasting an hour?