Lambda Calculus - Fundamentals of Lambda Calculus & Functional Programming in JavaScript

Just last night I found this excellent introduction to the Lambda Calculus by Gabriel Lebec [1]. It's one of the best I've come across and covers briefly history, building up combinators (using Smullyan's names) leading up to implementing Church encodings and gives Javascript equivalents (or approximations when not possible). The slides themselves are also very aesthetically pleasing, Gabriel has a good sense of colour and design [1] [VIDEO]

For anyone interested in the topic (combinatory logic as told through the medium of birds) I adore Gabriel Lebec's talk "A Flock Of Functions: Combinators, Lambda Calculus & Church Encodings in JavaScript" [VIDEO]

I found these two videos on combinators and lambda calculus recently. They're only tangentially related to Haskell, but they are the most approachable videos on the topic I have ever seen. [VIDEO] [LINK]

I suggest you to watch this video if you want to understand how 3 basic functions can be used to create whole language [VIDEO]

I would start with lambda calculus. If you pick the right intro video, they'll stray into combinators: [VIDEO] is very good.