One of the main reasons I like Perl is CPAN (Comprehensive Perl Archive Network) and the ease of finding, installing, and testing of packages it provides that solve a problem I was already trying to solve.
I would like to know of any similar repositories for PHP, Python, Ruby, Java, C++, Javascript, etc..., or better, a comprehensive list of such repositories. To date my list is PHP: Pear, Python: PyPi, Ruby: rubyforge, and Java: maven. What are the top repositories you go to for the languages you program in, or what repositories do you use to share your code?