There several of these in Bremen, mostly in public buildings, including the tax office, so anyone can walk in and use them. They are great fun to ride:
This site: http://www.flemming-hamburg.de/patlist.htm, also in German, is linked from the Sheffield Arts Tower wikipedia entry; it's got a bit more info for ubercompletists
http://de.m.wikipedia.org/wiki/Liste_von_Paternosteraufzügen...