This is a video of a woman demonstrating a spinning 'hologram generator' at a recent tech convention. Obviously, it doesn't actually project holograms, just 3-D looking graphics on two quickly spinning blades (previously: a similar device that people in the comments really wanted to make clear is not actually projecting holograms). Still, cool to watch. Although I wish whoever filmed it would have had the foresight to bring an actual high-res camera or phone to capture the action instead of the loaded baked potato they used instead.
Keep going for two versions of the video in case you think one might have higher resolution and like being disappointed while I watch Back To The Future II.
Thanks to zootghost, who agrees the future is always just a split-second away.