except for some 2005 and later models, they are not even x86 based, they are based on sparc. Windows 9x will never run on those. You will need a unix type OS, like Solaris or linux to use those. They are pretty much worthless for gaming since they always were professional workstations that had no compatibility with pretty much any consumer hardware.

I would like someday to get some sun boxes to play around with because they are cool, but I would have no actual use for them either.

I used some Sparcstations in college. Solaris was interesting to me at the time. It might have been the first time I used a *nix GUI. Web pages all looked strange with their fonts. I remember reading Matrox G200 / G400 news on those. Some version of Netscape. And using StarOffice. I don't remember what engineering software they ran on them, but I think circuit / logic design was one thing.

Later I was in a classroom that had a load of Sun "Sun Ray" thin clients that were only used to log into Citrix Win2K terminal server (remote desktop). Their Win2K server could barely cope with the load and would become quite slow, so I would use its Solaris instead.

I don't know what would be especially interesting about them now. Like a half hour of playing with the fairly typical old *nix GUI and then what? 😀 They were scientific / engineering machines.

I also used those in college for most courses that involved programming in C (operating systems, networking), and also a bit of Sparc assembly when studying RISC architectures. I have to say, I was quite relieved when they migrated the whole lab to Linux PCs around 2002, the old Sun workstations were painfully slow and the Solaris UI and tools seemed really primitive compared to what any serious Linux distro already offered at the time.

As was said in the other posts, totally worthless for any kind of gaming, and most everything else nowadays except really specific software. If you want to play a bit with Solaris it is just easier to get an x86 version, the experience will be practically the same.

I strongly agree with what's already been said - use them as a cool entryway to learn something useful about programming, OS and graphics rendering. They are "luxury computing items" which carry a lot of history with them.
If you're into assembly programming then it's interesting how the architecture vastly differs from the, for example, x86 - or at least what is exposed to you architecture wise.

With everyone else on not being able to run x86 software (such as DOS or Windows) and thus not suitable for running most games.

However it goes a bit far as to call them 'worthless for most everything else' too. Yes, a Raspberry Pi could out-perform most of them easily, but that applies to a 486 too. In other words they are firmly within the domain of retro enthousiasts. Now, if 1990s PC gaming is your only thing, they're not going to be up your alley, but outside of gaming they're as valid a platform as any other. Also, any 1990s-vintage stuff is going to feel slow and primitive around 2002. I had the exact opposite experience in university around 1997 - half the labs had 486DX33s painfully trying to run Windows 95, the other half had Sun Sparcstation 5s, with four times the RAM and CPUs clocked over three times higher. Of course they were faster... just as the Pentium 2 333 systems running Win98SE they installed a year later beat the pants off the Sparcs. New boxes almost always make old iron look&feel slow, regardless of architecture/platform.
The same applies to Solaris - just like you can't expect Windows 95 to have all the features of Windows 10, it's not fair to compare a 1990s vintage Solaris to Windows XP or indeed Linux with KDE or Gnome in 2002 or later. Yes, it's old and clunky, and not something one would want to do serious work on today (although if your work is on the command line, that may not be entirely true 😜 ), but it is stable, functional and if you worked with it in the day you could have warm memories of it.

Taking them on their own merits, the build quality of the earlier Sun systems (pre Ultra5/10, when they moved to using PC-industry ODMs) is astounding. The plastic they used is prone to yellowing and getting rather brittle after >20 years though. Sun's platforms tended to be more focused on I/O and stability and ease of use than competing RISC workstations (CPU performance was competitive in the 1990s, until the Intel-AMD GHz race, but never on the level of say the DEC Alpha, and graphics couldn't compete with SGI), which made them very popular in the server domain. At my work there are *still* Solaris/SPARC boxes in mission-critical production - many, many years after Sun got taken over by Oracle and basically stopped development.
I personally like the last generation of non-Ultra SPARC machines most, in particular the architecture of the SparcStation 20. The SBus expansion system is odd, but ideally suited to their pizza-box or 2U server systems, and the MBus CPU architecture is fascinating, allowing two different CPU modules to work together even if CPUs are not matched or even clocked identically. You could have a dual CPU module running at 50MHz and a single CPU running at 85MHz and somehow the three CPUs all worked together. Of course a system with sub-100MHz CPUs and max 192MB RAM belongs in a museum today, but again, that applies to your 486 too. And I know quite a few retro enthousiasts who have a SparcStation IPX 'lunchbox' still running as home server 😉