Brooklyn Brainery is a community-driven crowd sourced education group located in Carroll Gardens in Brooklyn. They offer a ridiculously wide and eclectic variety of courses, mostly taught by other people in the community. Things like: beekeeping, the history of Scotch, tree identification, and the secret lives of bacteria. The whole concept is really excellent.
If you're in the NYC area, check out the courses and see if there's something that interests you. Also, they are always looking for instructors, so if there's something you're interested in that you'd like to teach they are open to all suggestions.