You may be familiar with the Seed Savers Exchange in Iowa. As a member you can buy or exchange seeds with other members. They encourage heirloom seed saving. You can grow the same variety of Hollyhock or Sunflower that your grandmother grew because people have saved the seeds and passed them along for other gardeners to grow.
A relatively new organization is the Rocky Mountain Seed Alliance. The founders of the Rocky Mountain Seed Alliance spoke at the Denver Botanic Gardens in September 2015 – “Seed: the Future of Food”. Seeds saved from successful plants are uniquely adapted for the local environment which makes local or regional seed groups important.
Both of these organizations offer “Seed Schools” where they teach best practices in seed harvesting and preservation. The Rocky Mountain Seed Alliance offers webinars on seeds and has a seed school in Aurora, CO in August 2016
If you want to see some interesting videos about International Seed Banks see my earlier post on this site.