This is a recent demo by Disney Research of a virtual reality system they've developed that allows users to accurately interact with moving physical objects while in a virtual reality environment. In this case, catching and throwing a ball. An explanation that makes no sense to me because I'm stupid and my parents probably wish I'd been a virtual baby like a Tamagotchi:
We examine three visualizations: rendering a matching virtual ball, the predicted trajectory of the ball, and a target catching point lying on the predicted trajectory. In our demonstration system, we track the projectile motion of a ball as it is being tossed between users. Using Unscented Kalman Filtering, we generate predictive estimates of the ball's motion as it approaches the catcher. The predictive assistance visualizations effectively increases user's senses but can also alter the user's strategy in catching.
So yeah, if you were hoping virtual reality would soon have a lot more being able to play with balls, you're in luck. Obviously, I'll finally be able to live out my lifelong fantasy of fielding a game-winning fly ball in the outfield. Then my team will pick me up and carry me off the field a hero. *ahem* That's your cue. "We're not picking you up." Jesus, at least dump Gatorade on me or something. "Settle for pasta water?" Anything, quick, you're ruining the moment.
Keep going for the video demonstration.
Thanks to goldprawn, who agrees the scariest thing about virtual reality is not knowing when your roommate comes home with friends, and whether or not you're wearing pants.