What's the rarest or most unusual software item do you own?

I guess the PDP-11 operating system TRANTOR would be my most unusual piece. "Trantor was created by Steve Orszag of the MIT Applied Math department to access the CDC and Cray computers at NCAR for his fluid dynamics research. NCAR expected people to access the systems with an expensive piece of equipment that read punched cards, sent off the data over a synchronous modem using a proprietary protocol, and then sent output back to the printer. Not only was it expensive, who wanted to use punch cards? So Orszag bought a PDP-11 and hired undergrads to write software to use Emacs-like editing to create programs on the local harddrive, submit them using the proprietary protocol (which we sort of had to reverse engineer), and print and graph the results. ECC, CBF, and I were the early developers (there were a host of undergrad and grad student users as well, doing fluid dynamics). Somehow this was cheaper than the archaic method. Trantor was then a communications OS with built-in applications. We did the development on MIT-MC using the PDP-11 assembler and emulator." I recently found a copy and sent it to the original authors.