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.
If it’s people with asbergers or “higher functioning” autism, I honestly think riding public transit could have some potential. Stereotype of autists being into trains or elevators aside, as someone who suspects they have autism and is also extremely into trains and transit in general, I find that it really does calm me to ride transit so I do it for fun. When hanging out with friends (not super frequent) I still constantly find myself enjoying the parts where we’re just on the bus going somewhere the most, as in we’re just chatting, pointing to things out the window, commenting on the public transit system, things like that. Especially if you know at least some of them do have interests along those lines, it could at least be an option you can throw out there.