I worked with Mitch Altman to design the original Hackerspace Passport.
Mitch requested I design something he could distribute while on tour with Hackers on a Train to encourage people to visit their nearest hackerspace when traveling to new cities. The call was to make something simple to print, full of space to collect stamps from new venues, and reminiscent of an authentic passport. I also tucked in as many hacker in-jokes as I could for the sake of completeness.
I designed the layout, graphics, copy, and printing method. I also designed a process for creating laser cut stamps from a logo graphic and included samples along with the layout source. The project has been distributed and remixed widely, resulting in hundreds of different variations and several hundred thousand passports produced.
People have also created a gigantic array of stamps for marking passports across the globe. These vary from simple block stamps, to designs that allow hackers to mark the time and place of their meeting, to mechanical systems that emboss passports automatically.
The design is completely open source (CC Attribution SA). You can purchase your own at Adafruit, Seeed, or Sparkfun. Also you can remix your own from the source files here Hackerspace Passport, here Noisebridge wiki, and here Hackerspaces.org.