Hosting git repositories -- Gitolite allows you to setup git hosting on a central server, with very fine-grained access control and many (many!) more powerful features.

Portable GitHub system into your own server

Lightning Fast Graphing/Visualization

command line interface to access Dropbox API

Communicate with PhantomJS in Perl (Capybara+Poltergeist to Perl)

Test::Apache::RewriteRules - Testing Apache's Rewrite Rules