After spending some time in London, I got back to Berlin and was doing some electronics prototyping. Thinking about what the "hello world" of full-stack IoT might look like. Including sensing on an embedded device, connecting via MQTT and then visualising on a web application.
Learnt some interesting stuff about MQTT 3.1 such as it now supporting access over WebSockets. This makes it easy to write an app completely in the browser (no server-side component) to talk directly over a browser.