I stumbled across a unique website a couple of days ago.
This website let's you "reboot" old vintage operating systems.
It's actually just well choreographed pictures and audio, but it totally feels like the original reboot sequence for the operating system of your choice.
And they have some slighty old OS's, but they also have really old OS's like the Apple II GS and the Amiga Workbench.
My favorite has to be the Windows XP reboot, because they added the usual crashy XP bonk noises as XP crash reboots, pretty common for XP. XP never did have any easy shutdown/reboot it seems.
Here is the link:
The Restart Page - Free unlimited rebooting experience from vintage operating systems