Take a rope of some sort and have a large sheet or sheets draped over the rope so that the opposing teams cannot see each other and turn on strobe lights with kicking music. If you have a large club, consider putting all the guys up at the net and letting them play each other first, then the girls up front to play each other. This will help keep over aggressive idiot guys from killing girls and from groping them in the dark as well. Think through it. A beach volleyball sell in the cold winter makes this a winner to even sell sand volleyball at Camp