My suggestions would be Tcl/Tk or Pico 8.

Tcl/Tk is still the easiest way I have found to make small gui apps and the language and standard library is small enough to keep in your head easily.

Pico 8 is my recent love. It's a great way to make small retro style games. There's a free educational edition or you can pay $15 for the full version which has some extra export options. I've been playing with it for the past couple months and my kids from 6-11 have started to get involved. It's programmed in Lua and I and my kids prefer it at the moment to our previous attempts at Scratch.