It’s only October, and I’ve already discovered what your teenagers will beg for this Christmas: .

It’s the best way to bring virtual reality home right now. It’s also the funkiest: Strap on these light-up goggles and glow sticks, and you look like a character from “Tron.” Sold in a $500 kit, the neon gear’s real purpose is helping any old PlayStation 4 to track your head and hands—so you can literally be in the middle of a game. Look through the goggles, and you’re Batman reaching for a grappling hook that’s actually at your...