Software used to be fun when it typically involved only a few people making a closed system just work...
Software had to be efficient and elegant to run effectively within the limited parameters of the hardware which existed at that time.
Today it’s written sloppy as heck and they compensate by speeding up the processors.
A couple of trending languages that I think will be historically significant: Julia, and Rust. Both are very suitable for "fun" projects.
The combination of the Atom editor, Sublime (the Julia plugin) and Julia is excellent. I recommend running on Linux.