This is a very difficult request, because of TIMTOWTDI one mans well written code is another mans crap. Personally ...
I agree, and I think that regularly reading and thinking about the code/text of a wide variety of authors will improve your command of any language.
An interesting approach might be to take a few example modules with which you are not familiar, throw away the author's documentation (the pod that is, not the comments), and then try to write the documentation for the module based on the code and any comments.
Doing this you could hope to learn a lot both about good and bad code style and about good and bad documentation style; maybe also a bit about what aspects of a module should or shouldn't be documented. If you're doing it right I'd expect you also to spot some bugs in the process, which will give you a good opportunity to pay some tuition fees in the form of bug reports and patches. :)