Acorns have tannin in them that needs to be leached out of the nutmeat before us humans can eat them. The leaching process is as simple as placing your netted acorns into water and leaving them until the tannins have been removed. Historically this process was done in streams and rivers but you can do it in your sink or bathtub.
Once leached the nutmeat of the acorns can be made into flour, ground into coffee, made into soups, the possibilities are endless. If you have pigs acorns make a great pig finishing food.
Oak trees and their accompanying acorn mast can be found most anywhere. Bury a few acorns this fall and you will have tiny little oak trees sprouting up in no time. Yes it does take years as much as 15-20 years for oak trees to yield a harvest. Just consider it a gift for your future self!