From Astronomy clubs to the well known National Audubon Society and a variety of Meetups, there is probably a group out there with interests that are aligned with yours. If you want to try something new but don't know how to get started then this may be thing for you. Many groups love new members and are often willing to provide advice and resources to help you become the naturalist you've always wanted to be.
This page lists organizations that have memberships, newsletters or meet regularly.
If joining a group doesn't interest you, most of the citizen science projects have social aspects where you can interact with others on a more casual basis.