The very old school way: church/religious group. Doesn’t have to be fundamentalist/conservative - if you’re in a US metro area, I guarantee you have the more op

The very old school way: church/religious group. Doesn’t have to be fundamentalist/conservative - if you’re in a US metro area, I guarantee you have the more open-minded variants of all the major religions rather close to you. They’re often a good way to get plugged into long-term volunteer work, even if you aren’t particularly interested in attending worship services. (Personal taste: Episcopal Church, after growing up Southern Baptist. Childhood friend who got a harsher dose of Southern Baptist now enjoys occasionally doing stuff with her local Unitarian-Universalist congregation, and appreciates their youth programs for her girls. Your mileage will vary.)