Nikola Tesla is one of the genuine heroes of the hacker world, being an inventor, an engineer, and a true hacker of the 19th and 20th centuries. That's why we've moved heaven and earth to get our hands on the only currency in the world that honors his existence.
That's right, the Serbian 100 dinar note is a tribute to Tesla, as he was born in that part of the world. He later would move to New York City. He died at the age of 86 only a couple of blocks from where we hold the HOPE conferences. And, to make the story even more circular, it was at The Next HOPE that we introduced these bills to the hacker community in the United States. Suffice to say, they were a big hit.
These notes aren't easily exchangeable or even able to be found outside Serbia, making them a true collector's item. Add the hacker connection and you've got something really unique and cool. (NOTE: These bills have been circulated, but are in good condition.)