Since you axed, here are a few more suggestions for future topics. You might want to see if you can work in the idea of combinators, perhaps using simple parsers as a subject domain from which to draw examples. Then you could go further, if you wanted, into domain-specific embedded languages, drawing on the hyper-cool QuickCheck or Parsec or HaskellDB.

While not particularly advanced, list comprehensions are cool stuff, especially when used recursively. (See Koen Claessen's selections/permutations implementation (scroll for it), for a fun example.)

Cheers,
Tom