Would you like to start or help start an secular student group on your campus? The Secular Student Alliance has a free Group Starting Packet. They also offer legal assistance for individuals and groups who face opposition in trying to start a secular student group.
The Friendly Atheist has a nice highlight of a recent New York Times article that profiles a secular group at a Florida high school.
I would have loved such a group in high school! My high school was anything but welcoming for nontheistic students. Teachers were okay, but my fellow students wouldn't hesitate to condemn me for my questions. Participating in common school functions often required me to participate activities contrary to my values, like the Pledge of Allegiance or event invocations. I had no idea how to say no. Such a club would have helped me know I wasn't alone, and how to handle those let-us-pray moments in a simple, non-confrontational, polite but firm way.