You may already have a lounging area set up in your back yard, but you can kick it up to living room status by adding boundaries and making it really look and feel like a room. If your furniture sits under a pergola, then it's easy to enclose by adding curtains made of outdoor fabric to each side. Pull them back to the corners when you feel like communing with nature or close them for a more intimate gathering. If you're dealing with a wide-open space and no walls, then consider planting some tall hedges and creating an enclosure. Just be sure to leave space for a path to get in and out.