The https://freeCodeCamp.com open source codebase and curriculum. Learn to code and help nonprofits.
Freely available programming books
A delightful community-driven (with 1,000+ contributors) framework for managing your zsh configuration. Includes 200+ optional plugins (rails, git, OSX, hub, capistrano, brew, ant, php, python, etc), over 140 themes to spice up your morning, and an a
Linux kernel source tree