I am wondering, are there any small, self-contained NN examples that actually do something useful, while still being small enough to play with an implementation in my favourite programming language?
One of the simpler data sets available is the MNIST set of labelled hand-written digits. These days it should be easy to build and train a 3-layer NN for classifying those images.
The networks and data required to solve some of these is really small. I’m sure you can find some simple RL code out there to poke around in.