What started as an 'alternative' process (I was a D-96 devotee) Caffenol has become the only way I develop film that I want to be monochrome. Here's the recipe that I've been using for a long while. It rarely changes, but my dev times do.
More experimentation is on the horizon, with salt as a fixer, and maybe more exploration into peroxide reversal bleach
Caffenol has also worked well for me in cross processing colour, and C41 B&W stocks.