Ever since getting the Raspberry Pi Pico, there have been two experimental projects in the back of my mind.
The first is of course: how to run DooM on the Pico. Based on what I've seen, I suspect the main point of suffering would be the limited ram compared to a i486 machine. Most of the console ports back in the day managed to show horn things into fairly modest systems, and I bet the two cores would work great for doing video/controller input on one core while the actual game runs on the other. What I haven't been able to decide on is what path to take to explore that project. In my mind: I kind of see it as a more "Game Boy" like hand held with a screen and controls than anything else. I certainly don't want to do ASCII doom over COM port :P. It would also be preferable to have separate storage that can address the storage capacity of WADs without having to cookie cutter a level into available flash, making the hand held style even more appropriate.
Second is building what in essence would be a personal computer. In essence a lot like '70s kit computers such as the Altair, but imagined through the eyes of a geek that grew up in front of an MS-DOS machine. It's stuck in my head a while that the Pico is far more powerful than the early CP/M and DOS based systems, and that it isn't that complicated to connect the pico to external devices. From the prospective of fun, I think it would be neat to design a simple system around the Pico and built out something like a PC around it. On the downside, while creating a disk operating system in the vain of CP/M isn't that big a stretch: I can't really say that I fancy bootstrapping a toolchain to write programs for a custom operating system. But it's an idea that keeps floating around whenever I look at how powerful the Pico is.
As a side note, I kind of wonder how hard it would be to replace the CRT in an old Macintosh SE style case with a similar sized LCD panel. While gutting the rest of the insides, and just using it as the mechanical environment to mount stuff. Really, I'm not sure if that's brilliant or sacrilegious of such historic machines. Although to be fair, people have done some strange things with the cases of old busted Macs over the years....hehe.