first my apologies if this isn't the right place for this question but I think that th.CS is not the right place for sure neither is StackOverflow.
I really like functional programming and I think I'm a medium level guy in F# and understand the basic concepts of Haskell rather well - and yes I think I know/fell like I know what a Monad is.
Now I really want to take this to the next level and want to understand what all the talk about functors and stuff is all about. I just don't know where to start.
Read something about Lambda Calculus? Category Theory? Both I know a bit and I don't think that this is the right/quickest way to enlightment.
Maybe you can give me some hints on that.
PS: I'm not afraid of math and I don't get frustrated on excercises easily but I would prefere some intros/text where you can put some code down because this way you get the feedback at once.