Developer, never formally studied CS past high school -- what don't I know?
I work in OO Python professionally.
I know some basic automata theory and can sketch proofs of simple results like the pumping lemma.
I can understand and/or construct a simple grammar.
I know what a linked list, a binary tree, and a hashtable are, I know their big-O characteristics, and I'd be able to implement them in C if asked.
I've read SICP, and can easily manipulate recursion, closures, etc. I know how to adjust a function to ensure it takes advantage of tail-call optimization. I know how to "fake" OO using closures.
I can comfortably implement simple functions in Scheme or Haskell.
I've never played with macros or continuations. I know what a monad is, and have had cause to use them a couple times, but I'm not sure I know what the big deal is yet.
What don't I know?