The latest public version (pip install Hy).
I don’t generally install from the GitHub repo. I know that Hy is no big deal, just a Lisp skin on top of Python, but I really enjoy using it. Hy is an example of “done” software: it was written years ago, and just does what it is meant to. I have noticed comments on Reddit about Hy not being actively maintained, but as I said, it is “done.”