I have a text version of a Connect Four clone done. The AI for it looks ahead two moves, which makes it fairly impossible to beat unless you concentrate. I was planning to use this game for a chapter on recursion in my next book, but decided to publish the code for the text-version now.
Download fourinarow.py (This is for Python 3, not Python 2)
The code has few comments, but looking at its source code might be a good exercise for someone learning to program. It's available on the book's website in the Extra section.
I'd just like to announce that "Invent Your Own Computer Games with Python" has just sold its 1000th hard copy since it's gone on sale last May. I'd like to say a general thanks to everyone who has found this book useful. Thank you!
If you like the book, it would be great if you could write a review for it on its page on Amazon.com.
Here's a cipher disk that you can print and cutout to help you manually implement the Caesar Cipher. A program to implement this cipher (and break the cipher) is available in Chapter 14 of the free programming book "Invent Your Own Computer Games with Python" at http://inventwithpython.com/chapter14.html
Simply download and printout the PDF and cut out the two circles and place them on top of each other. The key number is whichever one is opposite the outer "A" letter.
Download the PDF
If you would like to change around the font or the logo, you can also download the original Photoshop file.
High resolution PNG files of the inner and outer circles are also available for download.