Only a few years ago - around 1973 - the author David H. Ahl published a milestone in computer games history. His book was called BASIC Computer Games and contained source code for a series of games that you could type in yourself - but actually meant for the use with DEC minicomputers.
After the microcomputer revolution began in the late 1970s, sales of the book went through the roof, and more than 1 million copies have been sold to date.
The book reviews nearly 100 games and explains the underlying mechanics in detail. It is still a source of knowledge for anyone who would like to learn more about software and game architecture.
Jeff Atwood has obviously been really impressed with the book, because he's about to go a perceived 100 steps further. In his github repo he collects the reimplementations of each of the games in the book in different, modern programming languages. C#, Java, Pascal, Perl, Ruby, Python, and VBNet versions of each program are implemented. Nearly 150 contributors helped so far, and the repo is very well maintained.
Not only something for indiegame devs!