While the most common rhetorical question of paleo-futurism seems to be, "Where's my flying car?" I am personally frustrated with the absence of a much more fun, futuristic innovation. The hoverboard.
In 1989, Back to the Future: Part II gave us a glimpse of 2015 and the next generation of personal, recreational transportation. I remember playing on a skateboard and imagining that in just a few years we'd all be whipping around like Michael J. Fox.
Sony has patented a "Segway-sans-the-handlebars" device, but it appears that we have quite a ways to go before we're hovering. Although, the geniuses at Mythbusters are certainly helping us along.