Norvig's Python programs to practice or demonstrate skills
Norvig is a beast. For those that don't know, he is high up in Google Research (AI director I believe) and also wrote the #1 AI textbook. He has the #1 AI course on coursera or edx too (can't remember which one). He's a big lisp advocate (look at his review of SICP on amazon), but also has the programs for his books in Java, and Python.