People are talking about Scala, F#, Erlang, Haskell and what-have-you. What is the point of functional? What is wrong with OOP? How does it all work?
Here are some videos you might want to look at. Maybe you find them helpful, maybe not.
Jessica Kerr: Functional Concepts for Object Oriented developers
This introduces the concept of immutability and pure functions and how your life gets better if you use those concepts in your everyday life. Of course, in DDD Value Objects and immutability is king as well, for the very reasons Kerr brings up in the video.
Brian Beckman: Don’t fear the Monad
This is a scary attempt at explaining monoids and monads. You may follow it, you may not. Don’t get too distracted or discouraged. Think of it monads in terms of LINQ and composability.
Erik Meijer C# Lecture, Functional Programming and Monads
http://www.youtube.com/watch?v=OrAVS4QbMqo
This talk is affected by Erik Meijers huge brain and is scarily influenced by Haskell, but makes sense if you saw the video above.
F# Creator Don Syme does a Tutorial
You should skip the first part unless you want to know from whence F# came. There is very little syntax info in this chapter.
Don Syme F# Tutorial Part 2
Loops, data structures, beginning of pattern matching.