The way is see it working:
One or two members take the role of host for the evening. They meet and greet and give the tour.
Members working on projects is a vital feature of open night: it demonstrates a working Makerspace.
We need to make sure members are happy to be there.
Part of the the hosts' role is to ensure other members' "quiet enjoyment" of what they are doing, by making sure they don't spend more time than they would like explaining their project to visitors.
Obviously a bit of engagement is nice!
I tried to take this approach on Wednesday. I think I was partly successful.