I have a self hosting Pi Zero W running Gentoo. It started as a joke, but I kept it because it's actually occasionally useful for testing new kernel releases.
I found a fun bug with it a couple years ago: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/lin...
It is still able to build software faster than it is released. It takes roughly a month to recompile the entire system :D