Teachable Machine is a browser-based demo of a teachable deep neural network. You teach it by showing objects to your webcam, and it learns to distinguish each object, which can then be used to trigger some output (show a .GIF, play a sound, etc.).
For example, I trained it using random items on my desk (an R-Pi, a mini keyboard, and a Wifi/OBD-II adapter)
It shows the confidence level of what it thinks it is detecting, and you can see real-time feedback on how various objects can be confused, or how a DNN system can be 'tricked' in various ways. This is a simple example, with relatively small training sets (a few seconds of seeing an object in a web-cam), but makes a good basic hand-on DNN 101.