There are many Jenkins-related events happening around the world: meetups, conferences, contributor summits, etc. You are welcome to join any of these events and meet other Jenkins contributors and users there.
Conferences and summits organized by Continuous Delivery Foundation: events list
Southern California Linux Expo (SCALE), Free and Open source Software Developers' European Meeting (FOSDEM), and other community-focused conferences
If you are interested in organizing an event, please reach out to the Advocacy and Outreach SIG. There are also Jenkins Area Meetup and Continuous Delivery Foundation CI/CD Meetup programs which include more than 100 local meetups in total. You can organize a meetup in your city or help with organizing existing meetups.