Contributing to Open Source has no barriers to entry, and is a great way to learn, build a resume, and have professionals review your contributions.

For example, I have no idea who half of the contributors to the D programming language are. I don't know their real names, age, sex, country, religion, politics, nothing. I don't know if they live in a mansion or in their mom's basement. I only know them by their contributions. It's as close as one can get to a pure meritocracy.