A $15 "Minimum viable computer"

Brian Benchoff offers the minimum viable computer, a "Linux Swiss Army Knife" that goes in your pocket.

Is it fast? No. Can it run a GUI? Also no.

But it can run Doom. Most interesting how minimum viability includes pocket mobility nowadays, without even thinking about it. And it is also intentionally designed, including a custom PCB, not just a bag of cheap parts jammed together (though it is also that.)