I've taught several workshops over time, on circuit bending both audio and video equipment, as well as how to build minimal circuits to produce sounds, and further experimentation with them. My workshops can be anything from a few hours to a few days. They usually end in a group performance in front of an audience that gives participants a possibility to showcase their accomplishments.
More than just showing people how to open up hardware and fiddle around with it's guts, I try convey a few more general ideas about reusing and repurposing electronics. Our surroundings bombard us with an abundance of technological advancements in a pace that makes us forget their value, while letting their inner workings remain utterly mysterious to us. If we go with Athur C. Clarke's third law, stating that:
we basically end up with massive landfills full of discarded magical artefacts, conveniently hidden from our sight in other parts of the world. I won't go too far into the environmental and societal impact our weird relationship with electronics has on our planet, as this has been done more eloquent elsewhere, but these are issues I consider important mentioning.