"I don't know if it's a sustainable industry, but there's definitely money in it," he said. "There's many ways you can link gaming and interactive entertainment outside because portable devices are getting pretty powerful — and so is the network. I can see it growing."

At Georgia Tech, the Atlanta school where Trip and Grace's "AR Facade" was created, researchers are using the technology to create "interactive dramas."

The games are "somewhere between a movie and a video game," said Steven Dow, a Ph.D. student in Georgia Tech's human-centered computing program.

"You can kind of choose your own outcome, and you can define your own way to win," he said. "In a way, it's a theater and a stage where people can step in to become an actor in the experience."

Researchers there are creating a game called "Four Angry Men" — based on the play — where players debate the fate of a young man accused of killing his father.

"AR Facade" had a more traditional beginning. Created over a five-year period, it started as a free traditional PC game that asked players to type in comments to interact with the bickering couple. More than 300,000 copies have been downloaded, and it earned critical acclaim for its sophisticated artificial-intelligence system.

Dow and other researchers spent a year trying to bring the game into the real world. They built a living room with a couch, a bar, pictures on the wall, a phone and other household staples. In fact, everything is real except Trip and Grace — the two cartoonish characters can only be seen through a backpack-mounted laptop worn by the player and a screen mounted from the player. The virtual arguing comes through a pair of thankfully comfortable earphones.

The goal of the research is to gain a better understanding of how humans and computers interact. Dow has studied dozens of gamers, watching as some have antagonized the characters while others have grown emotional as the quarreling intensified. One gamer tried to physically stop the fight, only to remember she was trying to block a virtual character from walking away.

The equipment that gamers strap on to enter the Facade world seems imposing, but the processing power that runs the system is no more daunting than what's found in an Xbox 360 console.

"This whole thing could run on your home game console," said Blair MacIntyre, an associate professor in Georgia Tech's College of Computing.

Professional voice actors recorded thousands of lines of dialogue to play the young couple's voices. As the player talks, a researcher types the words into a computer behind the set. They trigger certain reactions driven by several complex algorithm engines that control the drama, dialogue and even the facial expressions of Trip, a pushy blond, and Grace, an attractive and temperamental brunette.