Back in 2019 while I was still in Japan, I saw a video by user deramp5113, also known as Mike Douglas, about his Altair 8800c Project. He had managed to build a completely brand new Altair, nearly identical both visually and electronically, to the original Altair 8800 by MITS, made possible through using his own replica cases that he created for the Altair 8800 Clone Computer and various reproduction S-100 boards. I decided at that time that I wanted to build my own and got to work creating a huge parts list that I would need. I ordered everything and when I returned to the US on Christmas Eve, I had all the parts still in boxes in my bedroom.
It took several weeks, but I was able to build a working Altair 8800 and get original 1970s software up and running on it. I used the machine to help teach my Computer Club (and myself) about computing and just have a heck of a lot of fun at a low level. Back in June 2020, a few months into the COVID-19 pandemic, I worked on creating a queueing program in BASH and allowing users to ssh/telnet in to my home server and control my Altair.
It's pretty much always on and running CP/M v2.2b for Mike Douglas' 1.5Mb floppy.