I recently adopted a dog from a no-kill shelter (Atlanta Pet Rescue & Adoption if anyone is interested). I had been looking at dogs there for a few weeks, and last week I noticed they are running Linux on the computer at the front desk! Every time I've seen it they've just had Firefox open fullscreen to their web page, but it was quite clear they were running Gnome Shell with "Activities" and the Firefox icon on the top bar. That only made me more happy to adopt for them. It especially makes sense for a non-profit organization that I'm sure doesn't want to waste money on a Windows or Mac machine.
This also reminds me, several months ago I was riding the subway in Atlanta and I noticed on one of the really old monitors in the car I was riding it said GNU Grub Version (probably some really old version). I can't remember what is normally displayed on those monitors, but that one seemed to have not booted properly and the Grub readout caught my attention.
So has anyone else noticed Linux desktops (or other platforms) in unexpected places?