Well, this is certainly something I thought I'd never be writing about, but in retro modder fashion, surprises like this are coming up more and more recently, and I am all for it!
One of the most popular Mac operating systems of the past is Max OS X, Cheetah, released in 2001. It was actually one of my first Mac OS's to experience.
If you're lucky enough to still have your Nintendo Wii lying around from 2006, then you may be happy to know that you can now port this popular OS to it yourself, all thanks to a curious modder named Bryan Keller.
The Nintendo Wii has had random ports of different operating systems to it in the past, such as Linux, NetBSD and Windows NT, but never Mac, due to its complexities.

Bryan documented the long journey on his website, stating her first had to figure out if the Nintendo Wii had enough power, RAM and storage to be able to power Cheetah, in the first place, alongside determining if the software stack could actually be imported in some manner.
The software port was the biggest challenge, with days of bug-fixes, long nights and even modding sessions on aeroplanes to get this thing off the ground, literally.
I am no software nerd, but his research shows the sheer complexity of this task, and it's as if I were reading his journey in an entirely different language. That's before Bryan almost broke the entire Nintendo Wii when trying to boot it off a USB stick.
However, with a lot of incredible work a very early, working prototype of Mac OS X is now working on original Nintendo Wii hardware, allowing Nintendo/Apple nerds to explore this OS in an incredibly unique and useless way, but that's what makes it magical.
There are still tweaks and fixes required, for example, there's no sound output as of it yet, which is going to be another mighty task, and that's if Bryan wants to tackle it, but for now, this is the world's first Nintendo Wii with a working Mac OS inside of it. What a time to be alive. Great work, Bryan.
If you want to give it a go yourself, Bryan has made the disk image available to download, containing Mac OS X 10.0.4 Cheetah for the Nintendo Wii. You must have a software-modded Wii capable of running BootMii. The Wii Mini is not supported.