I still have grayscale Handsome Squidward on my calculator. In fact it's pretty much frozen in time since high school aside from putting lots of calculus related stuff on it.
@NovaSquirrel
Mine have seen renewed use for making music with Houston Tracker 2. HT2 is a pretty darn impressive piece of software.
It's got a bunch of assembly source code on it for games I never finished and probably won't. One of them was gonna be a simple Sonic-inspired game, though who knows if that would have gone over well on an LCD that's slow enough that you can get grayscale like this.