Well, we have elected officers who help the mentors to organize a lot of stuff and make sure everyone is working (along with each have their own particular duties to attend to). Then basically its just that the older members work and help the newer members learn things.
We have about 35 members, 3 advisors (2 in school, one out of), 3 engineers, and like 6 or 7
technical parents, and 4 or 5 parents who help us organize trips & finances.
Everything is built by the students and the students and engineers come up with a basic design together. Some of the particulars of the design are decided by the mentors/engineers (they do engineering...they should know what they're talking about afterall).
Involvement...well...most of the time when people are there they work. Occasionally we run out of things for people to do which leads to less constructive projects (i.e. playing games on the computer). Next year we hope to solve this problem, however.
Our chairman's submission isn't online (yet). But we have a place on our website for team organization
here.