Too often Adults decide on a project that is important to them, and the only involvement by youth is to do the work. Meet with the young ones and decide on a project. Many small projects are better than one big one. Let the kids identify a project that appeals to them, and have the adults supply expertise. If you have no juvenile members or relatives, consider partnering with a group such as the Scouts or Campfire Girls.
Many schools now require community service before graduation.
Contact your local high school and work with them to identify problems and remedy them. Every adult that I meet in the fraternal benefit system complains of the lack of participation by the young people. This is a great opportunity to get them involved. I know from thirty years of teaching school that the creativity and energy of the teen-agers is amazing. Join us in channeling these attributes into community service.