Functional programming

Does anyone here have any experience with functional programming? I've been learning OCaml and Haskell recently, but there are things which are really painful to do with them (interactive programs).

Found a trivial game written in haskell which I bet took months to complete:
http://www24.brinkster.com/srineet/para/para.pdf

I like it though.

Somehow I get the idea that someone just bumped this thread to make the point that he hasn't read SICP.