I collect slide rules - a type of manually-operated analog computing device, once the professional tool of every engineer, technician, surveyor, architect or rocket scientist, but made obsolete in the late 1970's by the advent of cheap "Electronic Slide Rule" pocket calculators.
Some of the best slide rules, not surprisingly, came from Germany - particularly the rules of Faber-Castell and Staedler.
I offer a home to orphaned and abandoned slide rules (I have a small collection). If you happen to have a neglected slide rule sitting around unused and unloved, and wish to donate it to a good and loving home, please bring it with you to Eurofurence. I'll be glad to take it off your hands, even if it's an exotic, like a Czech-made Logarex! Currently, my humble collection consists entirely of american-made slide rules, so examples of slide rules made in other countries would help a lot.