As a kid, I rarely saw lava lamps --- maybe a couple of times at Spencer's at the mall, or when I spent the night at the house of a friend who had cool parents. A couple of years ago, trying to relive my youth, I bought a lava lamp from eBay; it turned out to be a mere 12 inches tall, made in China, and within 6 months, I couldn't distinguish the liquid from the wax. Just recently, though, figured out that eBay has the OLD-SCHOOL lava lamps, 17 inches tall... Many are going for $75 or more, but I found one for $40-something. Pictured below, the good vintage one (right) next to the chintzy one. My camera takes terrible pictures, but my new "real" vintage lava lamp is the interesting thing that I remembered.