Today in project ideas I wish I'd get rid of:
An #rgbds (#gameboy / SM83 assembler) linker that turns the object file into ELF, allowing it to be linked into a linux program (and resolve symbols in doing so), coupled with a minimal CPU emulator with a few syscalls to be able to perform C calls/linux syscalls outside of the emulator.
...and then use that to implement the x11 or wayland protocol in SM83 #assembly and display things.
(I've been looking for excuses to learn these protocols)