FWIW, Cate does their dress up/ sit down dinner on Monday nights, as a precursor to their “Convocation” - their weekly speaker series. My understanding is sports get squeezed a little and study period gets squeezed a little, so they can fit everything in.
Related question: how often do the various schools have all-school assemblies? They can serve a similar community-building role as sit down dinners. But based on this thread, I am guessing assemblies aren’t a universal? If there aren’t assemblies, how do schools do announcements?
Cate does them every day for 25 minutes (except on Thursdays - when they do senior student talks instead). Assemblies are student-run. Kids sit in their advisory groups and there is a lot of raucous audience participation as clubs and sports and admin and whoever do their announcements.