Casual games are those Web-based entertainments your mom is no doubt playing while you hog the Xbox. But are they a real business? According to GigaOm, casual gamesmake up 10 percent of the videogame industry's $30 billion in revenues. A "hit" casual game can get as many as 7 million plays a month. And these free, ad-supported games may actually be a better prospect for marketers than regular videogames. Their audience is far more tolerant of TV-like interruptions than hardcore gamers. But when it comes to actual dollars, few developers are going to make real money from casual games. Most make a couple hundred to a couple thousand dollars a month, and no one is getting rich off an ad-supported model. Some developers are turning to micropayments — small charges for in-game items, new levels, or extra play modes — to help pad their wallets.