Seriously, I do happen to know a little about acorn flour - in old Japan they used to steep them in ponds dug for that purpose. I don't know if the modern Japanese do it the same way but when I lived there my neighbors used to make these weird little unleavened cakes out of the flour, more of a curiosity than actual nutrition. My old landlady told me they'd gather them during WWII to stretch the rice rations. Amazing what you can do if you have to.
One web site mentions the "hang the ground acorns in a cloth bag in your toilet tank" method.