On a plaza outside a hotel in Culver City, Calif., four people are stalking each other with PlayStation Move controllers. The devices look a bit like microphones, with glowing orbs on top lit up in pink, yellow and blue.
Video game designer Douglas Wilson is holding a portable speaker, blasting Johann Sebastian Bach's Brandenburg Concertos.
From afar, this looks like some sort of public performance art. But it is actually a high-tech combination of tag and musical chairs, called Johann Sebastian Joust.
As Wilson describes it, "It's half playground game and half a video game. But it's this interesting intersection between those."
Here are the rules:
The music playing in the background controls the flow of the game. It erratically changes tempo, and the players must change the speed of their movements accordingly.
When the music plays quickly, the competitors can move quickly. When the music plays slowly, they are forced to move in super slow motion.
Each controller has motion sensors to detect whether it's moved too quickly. If a player messes up — or is pushed by a competitor — the orb turns red, and that player is eliminated.
The players take their cues from music, rather than graphics on a TV screen. This means the game can be played almost anywhere. It also means that it might not technically be a "video" game.
"You could argue that it's not," Wilson says, "because there's not really video involved."
Wilson came up with Johann Sebastian Joust in 2011. He was inspired by a folk game he played with friends in Denmark. That game involves two players wearing blindfolds, moving in slow motion while attempting to be the first to tap the other with a wooden spoon.
His goal was to recreate that sort of interaction using video game technology.
"It's also really fun to see the facial expressions of your friends and to no longer be so tethered to this strange screen," Wilson says.
And, unlike most games for the Nintendo Wii and Xbox Kinect, Johann Sebastian Joust is physical. You're encouraged to chase or push your fellow players.
"It's a pretty open-ended game," Wilson says. "How you hold your controllers or where you stand? ... Are you allowed to kick other players? The game itself doesn't really specify all of that, so different groups of players start negotiating and enforcing their own social rules on top of the computer system."
Jesse Schell, a professor at Carnegie Mellon University's Entertainment Technology Center, says the basic concept of physical interaction is a novelty in itself.
"Video games that involve touching other people, that just doesn't happen," he says. "Video games are usually so much about just interacting directly with a virtual world."
Johann Sebastian Joust became a hit at conventions and other events, but it wasn't easily commercially available until now. Part of the problem was that the concept is so hard to explain.
Wilson says it was a challenge to present the idea to publishers. "It becomes this kind of question, like, OK, well, will this thing sell? Will people understand it? And so forth," he says.
So Wilson did what many indie game makers do these days: He crowdfunded the project on on Kickstarter.
Instead of risking going it alone, he teamed up with other indie designers to create a compilation of arcade-style games, called Sportsfriends. The games can only be played by people who are physically in the same room together.
After months of delays, Sportsfriends hit the PlayStation Store this week. The developers are planning a release for PC, Mac and Linux soon, as well.
Schell of Carnegie Mellon says that while Johann Sebastian Joust may seem like a novelty, or gimmick, there's more to it.
"This game is the tip of a much larger iceberg that is kind of coming our way," Schell says. "I do think we're going to see a lot of growth in the notion of games without screens or games that are designed to be played outdoors."
Schell offers this interesting, perhaps paradoxical notion:
"Look at it this way. Play is very old. Play is hundreds of thousands of years old. And occasionally, technologies show up and distort the way we play games. When computers first showed up, they were very much about single player gameplay — which is weird, because over the history of play, we play in groups, that's what we do. We play together."
Now, computers can handle more: Local multiplayer, online multiplayer. And now that technology has made physical games like Johann Sebastian Joust possible, Schell says, "It's reverted back to the traditional modes of play."