Creator of the TeX typesetting system. He began writing the definitive book on algorithms, decided that the existing mathematical typesetting systems weren't good enough, took ten years out to write his own, using a novel method of program documentation (literate programming), then started back into his book again. The most complex machine in his house is a pipe organ, he doesn't own a computer. One of the ScaryHackers?.
If you want to see lots of Knuth code, look in the WaikatoUniversity library. He publishes his program listings as books. They have: Tex: The Program, the source to the TeX typesetting system, this is in Pascal; The Stanford GraphBase, a library of code for working with graphs (the data structures), this is in C.
Here is CWEB, Donald Knuth's literate programming system for C and C++ (download the code, and you've downloaded the book!): http://www-cs-faculty.stanford.edu/knuth/cweb.html
Another, simpler, literate programming system that is language neutral: http://nuweb.sourceforge.net/
Notable: **noweb**, concept is based on **nuweb**, but it floats atop standard software tools.