Here are some links I want to save regarding getting more proficient with functional programming.
Try F# right in your browser - http://www.tryfsharp.org/Create
Try Haskell right in your browser - https://tryhaskell.org/
F Sharp for fun and Profit – Scott Wlaschin – http://fsharpforfunandprofit.com
A Functional Architecture in F# – Mark Seemann builds an ASP.NET Web API in F#, JUST F#, but along the way he gives a great practical overview of why functional programming will improve your applications. http://www.pluralsight.com/courses/functional-architecture-fsharp
(Requires Pluralsight subscription)
Functional programming design patterns by Scott Wlaschin - http://www.ndcvideos.com/#/app/video/2311
Underscore - http://underscorejs.org/
A library with functional helpers that will help ease your transition to thinking functionally and using collections effectively.