I was hooked on the idea of participating when I heard the purpose was to dispel stereotypes.
Engineer Stereotypes Redefined
Show my girls that there are good people in the world and how they can be one of them too, who then will grow up to be good adults, making good choices and raise good children.
Well... a friend, or just another human being you've never met asks you to participate in something. It doesn't take too much effort, but it's important to them, and perhaps it'll effect some positive change.