Here's an item from America's past I would not have imagined would make a comeback: The teardrop trailer. First produced during the Great Depression and designed in the Streamline Moderne style, the towable campers were lightweight, economical alternatives to full-sized trailers. They typically offered sleeping/lounging space, storage, and a makeshift cooking/food prep surface. Gas prices being what they are these days, teardrop trailers are back in vogue; some models are so light they can be towed by microcars and even motorcycles.
To see the widest variety of styles, head over to the enthusiast website Nick's Teardrop Trailer, where he documents original models like this sweet wood-paneled Cabin Car, a Petersen model with a lid that flips up to create a ceiling, and the Trailerboat, which comes with a detachable roof that turns into an actual boat.