College was a few years ago, but when I hear of functional programming languages, I think of LISP rather than C/Pascal/etc. (The books we had then had them as imperative language, iirc).
The trick to Lisp is that it is flexible enuf to be able to use in any programming language paradigm ever invented. Strictly speaking, Scheme - a derivative of Lisp - is more commonly associated with FP. From a purity perspective, Haskell, Mercury and SML come about the closest (see [link|http://www.cs.nott.ac.uk/~gmh//faq.html|Functional Programming FAQ]).