I see this sort of advice a lot, and frankly, it bothers me. There's nothing wrong with doing programming projects in your spare time, but it's hardly the most impressive thing you can do.
For a variety of reasons, there are many one-dimensional programmers out there -- people who seem to be only interested in computers and oblivious to everything else. Come on people, the world is wide. Programming is not the best way to become an enterprising, dynamic individual. Unless your company is anti-risk and boring, don't you want to hire people who are different from you? People who have taken crazy trips around the world and learned skills that provide lateral insights rather than just what you get out of sitting at a computer writing code and reading Hacker News?
If someone could provide evidence of doing something daring, that would show more initiative to me than a GitHub project.