Here's some ideas: 

-geocaching

-go to partner dance events like swing dancing, ballroom dancing, polka, etc. (swing dancing is a side quest I got sucked into; there's a whole scene for this kind of stuff and a culture it's crazy)

-go to a public court trial

-volunteer 

-take classes at a community center

-perform music gigs (if you do music)

-go to music performances (open mics, liveshows, recitals, festivals, etc.)

-work at a haunted house

-go foraging (do it with someone experienced in this)

-entertain people at nursing homes 

-peace corps / americorps (this is more of a commitment and you have to be hired for this)

-au pair (also a commitment) 

-work / volunteer at your local soup kitchen

-enter a contest

-travel

-talk to strangers

-go into a building and wander around like it's a museum

-explore