Browsing existing open source projects to learn/improve class design and design patterns

I was thinking of looking into some open source projects to find examples of class design, design patterns, and maybe even some AI / algorithm stuff.

I have had some people recommend against looking at open source projects to learn, but I feel it really works for me to see patterns I've learned and implementations I've considered actually working in published projects.

I was thinking fairly simple games with more focus on algorithms and "computer thinking" would be quite helpful since I am less concerned with visual elements currently.

I thought perhaps card games would be pretty useful (poker, hearts, bridge, etc etc) and perhaps board games.

Does anyone have any recommendations for simple open-source games or programs that might help illustrate good clas开发者_运维问答s design and design patterns and/or AI implementation?

Thanks!

I first learned design-patterns using the book Design Patterns in Java.

I understand it's not exactly what you're looking for, but I though the codes provided as example were pretty smart and "reader-friendly".