This from a former 49X student who's now working at Google:
Google hired me because of my extracurricular activities, not my grades. Nothing impresses interviewers more than a student who takes an active role in the computer science community, so get involved in open-source projects, build your own website, do PEY, or find a part-time programming job.
The resources are available here to accomplish nearly anything that you can imagine. But no one is going to just hand these possibilities to you; it's going to be up to you to discover what you want to know, do, and learn. It doesn't matter if you don't know what you want to do with your life, because even if you do, your plans will probably change.
Do something outside of your classes -- something that you love. Draw, paint, act in a play, take up fencing, join an activist group, learn how to fix cars, teach kids basic math, organize a camping trip, write a short story, start a blog, bake cookies for your class every month. It doesn't have to involve computers, and today you might not be able to dream of how it could one day further your career. But everything that you do helps to make you into a more interesting person and people really do take notice of these things. In the end it will be these extra activities, and not your grades, that people will remember about you.