Stay back and supervise but leave them alone. Provide pizza or what ever food they devour. They'll hide from you anyway, they'll want to go off and talk and talk and talk and talk.
If you have to be in the midst of it that might really ruin the whole thing.
What I do when there's a sleep over. I put all the kids in the den floor. They pull all the cushions off all the furniture in the house. They lean up against the front of the couch and chairs to recline and they have a whole stack of mom approved movies. They get as much popcorn and stuff as daughter wants to offer and drinks too. I am in and out of the kitchen a lot and so is everyone else in the house. But this way I can hear them when I am not even in the room. The sound carries into the living room and my craft room.
So I can hear them when they're talking regularly and I can wander into the kitchen if I hear something I don't approve of. BUT they don't know this. They think they're unsupervised for the most part.
I also don't go to bed very early, I'm a night person. I don't think they've ever outlasted me.