Yeah, I've been looking at those TI calculators for a few years, hoping to dabble in some Z80 assembly programming for nostalgia.

I've also been eyeing their TI-92, 92II, 92Plus, and Voyage 200 series of calculators. They use the 68000 processor and have qwerty keyboards. It looks like there is a C compiler for it (http://tigcc.ticalc.org/), so it ought to be possible to do some interesting things, like this Fuzix OS, or a FORTH, LISP or Lua interpreter, or a terminal program over a serial link to a battery-powered ESP8266/ESP32 to the internet over WiFi.