Today, after sitting in storage for over 20 years, my brother and I dusted off his old IBM PS/2 Model 50 (8550-021), with the goal of cleaning it up and making sure it still works. It was still working when he stored it, so it should still be okay today (barring any unavoidable degradation caused by the slow march of time). As far as he remembers, it's got DOS installed on its 20MB hard drive (and a bunch of games).
I've taken it apart completely so that I can set to cleaning it thoroughly tomorrow. Everything seems to be in relatively pristine condition (save for the case, which is battered in a grungy, industrial kind of way). A visual inspection didn't reveal anything blown or out of the ordinary on the motherboard or HDD/FDD riser cards, and from what I can tell without opening it up, the PSU seems to not feature any blown caps either.
Originally, I was planning on just getting some cheap PS/2 keyboard and mouse somewhere (turns out none of us owns any of those any more), but the more I was awestruck by the industrial beauty and elegance of the PS/2 and its modular internals, I felt overcome by a strong urge to do this machine justice - assuming it still works, I'm buying the original PS/2 mouse and IBM Model M keyboard. It's the least I can do.
I've also been looking at other ways to expand and upgrade the device (which I'll do only after having confirmed it still works, of course). I've found an AST Advantage/2 RAM expansion/SCSI controller 16-bit MCA card (with 4MB of RAM installed) in an online store, which would be a neat way to add some additional memory to the machine. It's a multifunction MCA card that adds 8 RAM slots and a SCSI interface to the PS/2. I'm not entirely sure how these additional RAM slots work (i.e., does any RAM get added to extended memory?), but for its relatively low price, it seems like an interesting exotic piece of hardware to own either way.
There are other, far more substantial upgrades and peripherals I'd like to add to it, such as the IBM 486SLC2-50/25 processor upgrade kit (incredibly rare and prohibitively expensive if you do find one) or a math co-processor (haven't been able to find one, and would be rather useless for running a few DOS games anyway). Additionally, there are rare things like an MCA Sound Blaster or SGI IrisVision (more information) that'd be awesome to have, but I doubt I'll ever find them. I'd also love to get my hands on a matching IBM PS/2-era monitor, but I highly doubt I'll be able to find one that is in relatively good condition, close enough so I wouldn't have to ship it (dangerous), and not incredibly expensive.
This (admittedly modest) project has me quite excited, and I can't wait to see if it still works. This is not some disposable, faceless early 2000s Compaq or whatever - this is an iconic and truly classic machine that deserves care, attention, and continued periodic maintenance, even if it'll only serve as decoration. You don't just throw out or dump an IBM PS/2, and I possess the skills and passion to keep it in working order, so why not do so?