Form factor and mobile devices aside (there are already plenty of good comments on that), I simply don't see any eligible programming language for this. I.e, so

Form factor and mobile devices aside (there are already plenty of good comments on that), I simply don't see any eligible programming language for this. I.e, something that can be learned in an afternoon or two, a single loop construct, simple variable management etc. Much like JavaScript used to be in the 1990s (up to including ES3.) Modern languages are just too much tailored towards software engineering, IDEs and static analysis, have multiple redundant layers of syntax and semantic sugar, and, even if you have managed this, the core language takes you nowhere as the meat is in APIs and/or frameworks. In other words, we may need a simple language that is more on the art than on the engineering side of programming, in order to be accessible for fun activities and exploration.