Apologies for invoking the power of @members but we really need some welcoming faces for our visitors tonight..
The 'quick' way of hosting is to set it up as a tour. Tell people when they arrive that there'll be a tour, and when, point them to teas and coffees, get them chatting among themselves.
Then do the tour, which will come to a natural end unless you get in to chatty mode in which case you can have a whole evening of interesting conversations.
Everyone who turns up is at the very least curious, which is a fine quality! And many have great projects in hand or in mind.