Now, here's a recipe for Korean acorn jelly

http://www.nytimes.com/2010/10/13/dining/13acornrex.html

This has inspired me, and I collected many different acorns over the past week to try cooking this week! (Though I will probably just make bread.)

Everything I found online said that there are two main types of oak, but I found five or six different types of acorn... and I wasn't even trying that hard.

http://www.backwoodshome.com/articles2/clay79.html
http://www.prodigalgardens.info/acorn%20recipes.htm