Not sure about something for your whole family, maybe a friendship boat for Illuminations, do tehy still do that? But for the children, our kids liked doing the Alice In Wonderland Tea Party at the Grand Floridian. We spent an hour alone! This year they are doing the Albatross Cruise out of Beach club. It is down time for us, and new adventure time for them. The Tea Party they say is one of their favorite memories! I hope they enjoy this one too!
Oh yeah, a kind of hidden gem is the Dance Party at Playhouse Disney. On the nights that Hollywood Studios does Evening Extra Magic Hours, stroll by Playhouse Disney. It is unadvertised but there is supposed to be a DJ inside and you can dance all evening with tons of different characters! That would be fun, and could create tons of memories!