Enlarge Text Whirl is a bit like Scrabble against the clock. You put together words from six scrambled letters for points. Available on Social Gaming Network (sgn.com) on Facebook and elsewhere. Social Gaming Network's game bar on Facebook lets players know what other games their friends are playing on the network. Enlarge PathWords is Tetris-like letter scramble in which you click on tiles to create words of three letters or more; the more letters, the higher your score. Host company Zynga.com also has its own social bar that displays on social networks to let players know if friends are online and what they are playing. Enlarge Dominoes, one of the classic games, along with Hearts, Spades, Sudoku, backgammon and chess, available on Mytopia.com. There are customizable avatars and virtual prizes. Casual games are making connections with social networks to make a play for even bigger audiences. The reach of online casual games is already impressive: One-third of people ages 6 to 44 have played them, according to market tracker The NPD Group. Globally, casual games on PCs, game systems and handhelds, played online and off, generate about $2.25 billion annually, according to the Casual Games Association. SHARE GAMES: Tell us what you play online By playing nice with social networks such as Facebook, expected to hit 100 million users by year's end, the casual game category can only increase the stakes, says CGA president Jessica Tams. "The introduction of platforms which create opportunities for accessible and family play have raised the awareness of the fact that games are played by everyone, everywhere," she says. In the past two months, two new online gaming hubs, Cafe.com and Mytopia, have launched with features that let players connect with friends on the Web and through various social networks such as Facebook and MySpace, as well as Bebo and Hi5. Cafe.com features drawing game Sketch-It!, along with the more traditional Concentration and Sudoku; players can buy game "boosts" and outfit "Mini-Me" avatars. Mytopia.com focuses on traditional games such as backgammon and dominoes, and also has virtual currency for prizes and upgrades. Mytopia founder Guy Ben-Artzi says he created the hub to "build bridges" between online islands like Facebook and MySpace. Two popular existing networks, Zynga and Social Gaming Network, have begun adding their games as applications on social networks. More such combinations are on the way, because the revenue potential from advertising, subscriptions and virtual items "is enormous," says Ross Popoff-Walker, a researcher for Forrester Research. "It's a huge audience, (and) there are a lot of different experiments on the Web taking on elements of gaming and the traditional social network." Social Gaming Network (sgn.com), which opened in August, has seen its WarBook game attract more than 33,600 daily users on Facebook since becoming an application last fall. "It's a once-in-a-generation opportunity," says SGN co-founder Shervin Pishevar. "You have free access to all these users looking for fun and engaging experiences with their friends. We're connecting them in ways that wasn't really possible before." Over the past two months, since gaming hub Zynga made its games such as Texas Hold'em and Scramble available on Facebook, its audience has grown from 1 million to 2.3 million players daily, says founder Mark Pincus. "This is clearly penetrating a mass market." Historically, games such as Popcap Games' Bejeweled helped fuel casual games' growth in versions for the Web, cellphones, handhelds and game systems. Electronic Arts' Pogo.com rose as a dominant casual games hub that began offering subscriptions (currently 1.62 million) as well as downloadable games. When online Scrabble clone Scrabulous last year saw its Facebook following grow to nearly 1 million, Pincus says, "social gaming got on the map, and people were asking 'Is it one game or an industry?' "Social gaming has continued to grow," he says. "For the first time ever, digital games can start to penetrate people who never played games before." Today, Scrabulous has more than 3.5 million registered users with more than 600,000 playing daily. It remains available on Facebook and online (scrabulous.com) despite Scrabble trademark holders Hasbro and Mattel trying to shut down the game, created by Jayant and Rajat Agarwalla, brothers who live in India. Neither Hasbro, which controls the trademark in the USA, nor Jayant Agarwalla would comment about legal developments. Hasbro says EA plans to release a free social network version of Scrabble in the near future. As for the attraction of casual games, Agarwalla says they "provide quick entertainment for users without pinching their wallets. People can take a quick break from work, play a few games and get back. It's faster and I guess healthier than drinking coffee or watching TV." And the social aspect is important, he says. "When you play Scrabulous, you stay in touch because the moment you are thinking of a word, you are also thinking of your opponent. And that's what counts." University of Texas law student Matthew Tominey, 24, says Scrabulous provides much-needed breaks during studying for finals. "I would say it makes me happy, even though my win/loss record is abysmal." Readers: What are your favorite casual games? What do you play on Facebook? Share your picks and opinions in the comments below. Enlarge One of the games on new Cafe.com, Sketch-It! is a cross between Etch A Sketch and Charades. Players must get competitors to guess a secret word by drawing the object using a palette of colors. Newcomers get 10,000 Cafe coins (virtual currency) to outfit their "Mini-Me" or to use during games as "boosts." Guidelines: You share in the USA TODAY community, so please keep your comments smart and civil. Don't attack other readers personally, and keep your language decent. Use the "Report Abuse" button to make a difference. You share in the USA TODAY community, so please keep your comments smart and civil. Don't attack other readers personally, and keep your language decent. Use the "Report Abuse" button to make a difference. Read more