The 90s gave us two beautiful gifts of technological advancement: A ridiculously overpriced calculator you could cheat with in math class, and one of gaming's earliest, goriest first-person shooters: Doom.
Lazy Game Reviews brought these two together with a tutorial for running Doom on a TI-83 graphing calculator. He uses TI-Connect Graph Link Software and game software from ticalc.org to load everyone's favorite nameless demon-battling Marine onto the 18-year-old machine. Ticalc.org also hosts downloads for Tetris, Super Mario, and more old-school games.
It's practically a law of tinkering today: If it has a screen and keys, it'll run Doom. The game's software designers wrote the code to be more compatible and flexible than its predecessor Wolfenstein, so it was easy to port to other devices after its MS-DOS release. They probably didn't have piano keys or toasters in mind, but those, of course, will also run Doom.
Even on the "Too Young To Die" difficulty setting, the game runs slowly and responds at the pace you'd expect for a 6 MHz microprocessor. Still, it's definitely playable Doom, and a tutorial I would have killed for in calculus.