Strange that the post makes no mention of the Little Schemer series, because teaching you to "think Scheme" is exactly what those books do. Some people are put off by the weird style (combination of children's book visuals and socratic logic problem presentation), but they work!

I struggled with The Little Lisper (as it was called at the time) in school but as I approach the other end of my career I've given some thought to working through it again. I think it would come a lot more easily now. Though I looked at Haskell maybe 10 years ago and never got traction with it.

Functional or declarative programming styles appeal to me, and I love what I've learned of Erlang but never really had a job where I could use it. Used SQL a lot and quite like it as well.