This is for people that I live with.
I don’t mean any lame team building exercises, but casual group activities. It could be something mundane like organizing a trip to the store together. Movie trips would also be fine as would showing something on the home projector, though I feel like there’d be more distractions and temptation at home.
Is there any public transportation in the area and do they feel comfortable riding on it? If so and if they’re receptive to it, you could potentially “collect” transit lines, where you ride one line from beginning to end to see the view outside, potentially explore the areas along the route, and “collect” routes and corridors they’re explored, take pictures (of the surroundings if they themselves don’t like being photographed), and basically explore different parts of the city that way. Usually most transit networks are fairly quiet at night as well.
Obviously the viability of this depends on what level of transit network you have, the more extensive and built-up the better since that can reach more places faster.