Ok, here's an idea: Zork-themed keycaps.
It's retro, it's one of the very first keyboard text adventures -- and it would be easy to make this into a 3d printed keycap.
(Ok, I'm assuming it would be easy.)
Just take that text as a vector object, put it on top of the keycap shape, and extrude it a bit, maybe rough up the surface with some imperfections. Also, a grue keycap would be nice.