You probably can't name one he hasn't played around with (and I'll admit -- I'm an enabler with this). He certainly has his black belt in C++, JavaScript, and Ruby, but he's crazy about Lisp and has recently gone on a tear with Nim.
He's written his own editor ("I want it the way I want it!") maybe four times in different languages, just because. He's always teasing me for being a vi user ("You're stuck in the 70s!")
He really loved it (and I think plans to write some more stuff with it).
I'm coming up on 50, so all of my friends' parents are roughly the same age. The big crackup for me is that they're all worried about their parents falling for a phishing attack or having to update operating systems that haven't seen an update in ten years.
When I call my dad, he wants to get deep into compiler theory. Or talk about Rust. Or moon about how the world would have been so much better if Brendan Eich had just implemented Scheme. Or he'll talk about how much he loves TeX.
You know, he complains that he's not as sharp as he used to be. He's always warning me to take care of my body, because "mens sana in corpore sano!" But really, I just don't worry about him at all.
He's also one of the happiest people I know, and absolutely one of the most well read (I'm an English professor; I'm surrounded by well-read people. It's kind of amazing how many books he's read in his life).
