The entire source code for a huge array of Infocom text adventures and interactive stories is now available on Github, thanks to historian and archivist Jason Scott.

https://github.com/historicalsource?tab=repositories

Among the titles are:
– Zork I, II, III
– Leather Godesses of Phobos
– Nord and Bert Couldn’t make Head or Tail of it
– Stationfall
– Hitchhiker’s Guide to the Galaxy
– Bureaucracy

Source: Gamasutra – The source code for Infocom’s classic text adventures is now on Github