Game On

Ask Patricia O'Brien, 36, about her college years and she readily admits to having had an addiction. Her habit? Tetris, the puzzlelike computer game that resided on countless hard drives during the 1990s. "I could play for seven or eight hours straight," says O'Brien, now an advertising sales manager in Chicago. "It was addictive [and] very satisfying while I was playing. But by the end, I felt like I had a hangover." Lately, she's had a relapse: Diner Dash, a download-for-free "casual videogame" in which players must serve grumpy diner patrons.

As the mother of 6-year-old twins, O'Brien doesn't fit most people's stereotype of a serious gamer. And until recently, her new addiction was her own dirty little secret. "Sometimes when everyone is in bed, I play for hours at a time," says O'Brien. "It helps me wind down. But then in the morning I'm exhausted."

She's not the only one seriously hooked on casual videogames. In recent years downloads on sites like Yahoo!Games and pogo.com have become something of a furtive national pastime among bored office workers, insomniac moms and chronic procrastinators alike. Like the Froggers and Ms. Pac-Mans of yesteryear, games like Bejeweled and Mystery Case Files take little skill to learn but are challenging enough to keep players fixated on their screens. Such games are in contrast to "hardcore" titles that have darker storylines, are more complicated to play and are favored by Xbox and PS3 devotees.

The hardcore crowd still dominates the $16 billion videogame industry. In contrast, about 145 million casual gamers will spend $690 million this year. And according to the new-media research firm Interpret, casual gamers average 5.1 hours of game play each week, up 28 percent from the year before.

Casual-gaming developers and Web sites, however, have yet to fully capitalize on their increasingly dedicated fan base. The industry is struggling to "find better ways to monetize its audience," writes James Kuai, a research analyst at Parks Associates. Of particular interest: the armies of women age 25 to 45 who play the majority of the games. It's a worldwide market that the Casual Games Association says could potentially generate $1.5 billion in revenue this year.

Ironically, the industry can't rely on sales to generate that kind of cash. The majority of players—legions of loyal but budget-conscious moms like O'Brien—don't actually pay to play. Instead they rely on no-charge Web sites or simply download their favorite titles for free.