Also, if you like the vibe around races, a lot of (running) races are often looking for volunteers. For example: https://nhmarathon.com/volunteers/

If you like hiking, consider going to Appalachian Mountain Club (AMC) events. You can search here: https://activities.outdoors.org/search/

It helps to sign up a few weeks in advance. E.g. NH Young Members (20s & 30s) has the following event this weekend, but you can only sign up for the waitlist at this point: https://activities.outdoors.org/search/index.cfm/action/details/id/141555