One of my favorite Talks on #39c3 was "Watch Your Kids: Inside a Children's Smartwatch" by @trusted_device. The technical part was interesting, but let's face it: there are lots of broken IoT-devices out there.

The main reason I'm recommending it is because the way it was presented was so good. The speaker did some very good storytelling and very entertaining examples. They also explained the more technical part or abstracted it away so my not so tech-savvy friends could follow nicely, while keeping the talk and the slides detailed enough so I feel like I know what they did. Please watch this talk!

https://media.ccc.de/v/39c3-watch-your-kids-inside-a-children-s-smartwatch