I recently became involved in the P2 community, the new propeller microcontroller from parallax (which just hit rev C). There's some very talented people there doing interesting things with it.

Some of them have been programming it before it was even proper silicon, when it was being developed via FPGA. Lots of really in-the-weeds discussions on machine code and cycle timings and such. Worth diving in if you like seeing "how the sausage is made."

One of the current projects is implementing a sega genesis/megadrive console, using the different cores to emulate different components: https://forums.parallax.com/discussion/173381/console-emulat...