Infocom text adventures were some of the first PC games I ever played. I was too young to properly wrap my head around them at the time, but they still mean a lot to me. Thus, I'm happy to report that archivist Jason Scott of textfiles.com has uploaded the original source code for all of them to GitHub this week. Digital historians and aspiring coders alike can poke through the bones of these videogame dinosaurs, and hopefully learn a few things about the do's and do not's of text parser interfaces. You can find the code here in the Historical Source section of the site.
For someone just wanting an adventure to puzzle through, the archived source code is of limited use. If you're after something nostalgic to play, Archive.org contains many DOS originals, emulated and playable in your browser. Being a subject near and dear to my heart, I'm happy to see both kinds of archival done. The playable final products are some of the best known games of the early to mid '80s. If you really want a brainteaser (and a workout on your old-timey turns of phrase), check out Nord and Bert Couldn't Make Head Or Tail Of It. You have been warned.
Infocom's games were developed using a bespoke language called ZIL, or Zork Implementation Language. While this will likely seem baffling, alien and possibly terrifying to anyone poking around the source code, there is a handy guide-book to the language here on Archive.org, written by Steven Eric Meretzky. It warms my heart to see both the original code and secondary resources like this so well preserved. While of limited practical use these days (modern tools like Inform or Twine are vastly easier to work with), it's both interesting and educational to see how we got here.
The only concern is that Activision technically own the rights to Infocom's works and could, theoretically, choose to crack down on these nostalgic good times. If anything, that just highlights how important it is to have these things independently and comprehensively archived. In this era of eternally extended, Disney-led copyright, even historians have to navigate the gaps between the mega-corporations. A fact that's both sad, and extremely cyberpunk.