I would check around to the colleges and universities and see if they offer some sort of junior engineering/science program as part of their cooperative learning. We're using Utah State University who offers a junior engineering program for schools. www.engineering.usu.edu/jrestate/home.php
Check to see if you have a Mad Science franchise near you. They can come and do lots of hands on experiments for your group. Also, what part of the country are you in?