Using Python to teach kids programming
Python for Kids (http://inventwithpython.com/) – free ebook for beginners, as early as age 7
Number game, design improved by my son: http://blue.netnation.com/~ftibet/projects/python/guess_number2.py
Numerical Methods with Python as front end (http://en.wikipedia.org/wiki/List_of_numerical_libraries). My own project in developing analytical suites for the mobile industry.