Every Friday, this repurposed little piece of networking gear in my living room builds the latest version of Chocolate Doom from Git, and automatically plays through over 600 hours of demo recordings to ensure that demo sync works as intended.
The machine is an Edgerouter Lite 3 running OpenBSD and I specifically chose it because it has a big-endian MIPS CPU. So not only is it testing that the demos play back correctly, it's testing that they'll play back correctly even if you want to use weird hardware and an uncommon operating system.
It's kind of funny to think - this machine has no screen, nor does it have any way you easily *could* connect a screen to it, but nonetheless - it runs Doom. Silently, visibly, internally, it is playing Doom, at around 50x the normal speed.