Make a small spray paint stencil or vinyl sticker that represents your crew, or inspires people to think differently, and put them around your town or natural areas in subtle, cleverly inconspicuous locations.

Explore your area with Alltrails, or a similar app, finding new hiking or biking trails.

Urban exploration: creep through abandoned buildings, climb fire escapes to reach the rooftops, use catwalks under bridges to cross roads and rivers, scurry through large water drain pipes and abandoned steam tunnels.

Start a lucid dreaming competition with your friends, and share your experiences every morning. As you all develop more dreaming skills, you can share them with each other, and slowly become the masters of your dreams.

Come up with scavenger hunts that guide people into the coolest, hidden areas of your town, using clever clues, and share them online, similar to geocaching.

Pick up rubbish off the ground, one area at a time.

If it doesn't exist publically in your country, get equipment to either test air or water quality at several spots around your community, and then share them online through posts, or by hosting an Ushahidi map. Encourage others to chip in.

Get your gang to volunteer together to help homeless, elderly or disabled people once or twice a month. You will both bond with your buds and gain new perspectives from the people you work with.

Arrange spontaneous dance parties in public with little flash mobs made up of your mates. Try to get strangers to join in on the fun. Disperse after one song, so you don't get in trouble.

Learn to identify the 10 most common trees in your area, then the 10 most common flowers, the 10 most common weeds, the 10 most common birds and the 10 most common insects.

Explore local theater, try to find weird niche performances at churches, swingers clubs, primary schools, corporate retreats, futurist festivals, government events, and street corners. Make sure to cheer loudly and throw flowers.

Just came up with another idea, suggest stuff to OpenStreetMaps if the area needs to be edited or added.

Edit: and rate stuff on yelp, TripAdvisor, or something else like that.

Geocaching is a conduit to so much fun, so definitely keep that one up. When I first moved to SFBA it was the top activity that led me to discovering awesome places to return to. It's an excuse to get out with friends, and at the same time an activity to do when you're already out with friends, or solo, on a first date, or when you're watching your nieces and nephews.

Photography is another hobby that helped me find cool places. The wikishootme site shows places that need CC licensed photos, in case you need a photography sidequest goal. https://meta.m.wikimedia.org/wiki/WikiShootMe

Taking geotagged pictures wherever you go also lets you see where you have been on a map, and also where you have not been, which can give you ideas for new places to explore. Use an interval timer to make sure you take photos every N minutes while you're out, then look back on what you did. Or have everybody in the group photograph the same thing, then see how different people used perspective.

If you're in an area with lots of shops, spend at least 2 minutes in every single shop on the block, no exceptions.

I love The Book of Questions for conversation starters, so that's always good to have handy. Take it out with you on a walk with friends. Also if you have a flipper zero there's a questions app that is similar.

I keep kites in my trunk, because if it's ever windy and you have nothing to do, you might as well fly a kite. I also keep a picnic blanket in my trunk too, for spontaneous picnics and park naps.

Find or make a list of parks in your area and visit every one of them. Same for other geographical things you maybe interested in, like lakes, book stores, ramen restaurants, hilltops.

Have your whole group each make an alter ego and spend an hour or afternoon getting to know each other's alter egos. Explore personality traits that your real personality doesn't have.

If you have birds in your area, try finding and identifying them (for example by using Merlin Bird ID).

I’ve recently switched from Geocaching to Ingress. It has very similar benefits and doesn’t require digging around a bunch of ivy.

https://www.randonautica.com