A few days ago, at the main train station in Munich, subway level:

At least this series of payphones (there are different models with a touch screen in working height or with a camera) runs some form of Unix: they run WindowMaker which is only available for X11 as far as I know.

(I don't know if it's Linux or some BSD; and most likely the display component is a separate system from the actual phone. Note that some payphones at least in Berlin may also be equipped with a wireless access point running Linux, that could be even another system in the same payphone.)

Still it's amazing to see where Linux is today. Have a wireless router? Have a DSL modem (e.g. AVM Fritz)? Payphone? Bottle deposit machines (e.g. ALDI)? next generation of mobile phones? - Linux is just about everywhere where people are not exposed to the mouse. :-)

[Update: Daniel sent me an older picture of the phone display booting, it looks like being a SuSE. Funny (though not surprising) to see that the display is run non-rotated during boot (regular VGA), and when the driver is loaded it turns to the Portrait view.]