One of the best ways to engage the current generation of youth is to give them a chance to serve. Service learning programs are engaging and appealing to many types of students. A topic like biology may appeal to future scientists, while working with children may appeal to future teachers. An example of a program that offers both is featured in the Raleigh News and Observer.
There are many programs that combine service-learning and science, such as St. Louis Science Center's Youth Exploring Science and the Elementary Institute of Science's Commission on Science That Matters. Of course, there are many more youth interested than programs available, so I hope you will consider this as an option for kids in your community.