Teach or tutor
Many organizations need class instructors. For enrichment (noncredit) classes, oftentimes the only credential you need is experience. Try your local college or university, art center, or parks and recreation center. If you have aptitude and patience, you can tutor local students in math or English. Connect with local school principals and teachers to get started.
Or start your own program based on your hobbies or interests, as Dennis Golden did. He's the founder of IM-Safe, an organization that provides personal safety training, which he began after retiring.