If you could build your own private universe, just for the one you loved, what would it look like? There could soon come a day when we will have the computing power and tools to do just that -- at least in a virtual sense. Add in ongoing advances in virtual reality (haptic interfaces, brain-computer interfaces), and who's to stay we couldn't trick the brain into thinking our virtual creation is "real"?Shades of The Matrix? Not necessarily. We can use that power for good. Check out this viral video called World Builder, a short 9-minute film by Bruce Branit, a visual effects artist based in Kansas. The story is siple enough: a man uses cutting-edge holographic tools to create a world for the woman he loves. Branit shot the live action in a single day, although it took a full two years to complete all the computer graphics. World Builder has been making the rounds in the blogosphere over the last couple of months; at last count over a million people had seen it. It's a nice reminder of what is already possible, both scientifically and creatively.