Each language have its strengths, and what you seem to enjoy is real time evaluation, so compiled languages are not a real option.
On the same point, languages with a REPL might be fun for you, I could think of:
Those 2 languages are the trend recently but also still quite a niche.
(I understand those are not JS nor Python, but I think bringing those to your attention could help you broaden your selection...)
Why do I propose them? Because they are fun and will teach you some good practice and some of programming heritage (Lisp dialect with Clojure, Functional Programming with Elixir).
They also have a nice eco-system so you'll have all the tools you need.
Personally, I use both for small projects:
Those are just my 2 cents. A lot of other languages have potential as well.
Eryk Sawicki Glad I could be of some help.
Clojure could be a better choice on the long run, because you'll use JAVA Api that is still quite popular.
Also, there are some good resources for learning Clojure, like koans, you can search on Github.
If you want to make more graphical applications, Clojure can use the Swing library of JAVA to make GUI applications, it might be something more appealing that command line programs.