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.
Not an exact answer to your question, but:
One of the most important parts of e.g. company events was that I have a place for retreat; and acceptance of everyone that when I leave for a while nobody would stop me.
Ensure they know that you won’t be angry if they leave (early or even just for a few minutes).
And maybe even see beforehand if there are places that are suitable for such a retreat, which depends on each person individually but at least for me almost any park/canal/whatever-is-marked-as-green-on-a-map is suitable as long as there are parts with only few people.