Looking for Projects having extensive usage of (mostly used) design patterns

I want to get my hands dirty with 开发者_开发百科some projects (in C++) which have used design patterns extensively.

I have already read design pattern documentation (as well as code) from net and other books (gang of four and Head first), but i am looking for a place where i can get already implemented projects (using design patterns), get my hands dirty with them, understand them, enhance them etc.

Could anybody point me to a place(s) from where I can get design experience in the best possible way? (Please note: Language C++, Complexity of the project can be intermediate to difficult)

ACE is a good example - uses many concurrency and communications patterns. There's a list of related tutorials on their website here.

If you are feeling ambitious take a look at Loki.