I really enjoyed programming in Elm as a starting point. Elm avoids type-classes, which tend to be the biggest hurdle when starting to learn Haskell. Plus, you can design a nice web app in the process (versus, say, process CSV files). After I became comfortable with Elm, learning Haskell, type-classes, lazy evaluation, etc., made significantly more sense to me. For instance, `do` syntax is great, but it's not obvious what it really is doing, at first, unless you've programmed pure functional languages without using `do`.

Also, learning Idris is another great learning exercise if you want to stretch the ways to think about programming.