Based on my daughter and her friends, involvement in Lego Mindstorms robotics and First Lego League competitions is another great way to get girls interested in programming and technology.
YES. I am male, but this is how I got into hacking. Absolutely brilliant way to merge tech and play.
I can second this—I am not a woman myself, but my dear sister got into programming that way. (I did too.)
I wanted a Lego Mindstorm kit so badly as a kid, but my parents never got me one. I think my life would have been a lot different if my home situation had at least afforded me that one thing.