I think craic from Irish would fit into this. Not sure if there's a broader category there.
My understanding is that craic means to have a good time with good people, and that's exactly what gesellig is.
Gesellig might have broader application in this context though, as an event can be gesellig, a person can be gesellig. It's am adjective. It seems craic is used for all sorts of other terms which do not apply here.