Casinos are the hottest real estate in today’s heady world of social gaming.

From Zynga to Caesars, deep-pocketed companies are increasingly looking to get a piece of the action.  On Tuesday, Seattle-based Big Fish Games staked its claim, acquiring the maker of one of the most popular social casino games, Card Ace: Casino.

The deal, gives Big Fish a seat at the table of the fast-growing social casino market, where consumers connect with other players in real-time using their smartphones, tablets and PCs to play poker, blackjack, roulette and other felt-table classics. The parties are not disclosing the price of the acquisition.

The games are just for fun – gamers can’t actually win any money. But the house still makes out OK, since many players choose to spend real money buying additional virtual chips to supplement the pile of free chips they’re given to start off.

Social concepts, the company that developed Card Ace: Casino and whose backers include Tesla Motors founder Elon Musk, does not disclose its financial results, but the Card Ace app currently ranks among the top 10 grossing iPhone and iPad apps thanks to in-app purchases of virtual chips and other virtual goods.

For Big Fish, which is known for single-player games and which generated more than $180 million in revenue last year, casino games provide a perfect bridge into the world of social gaming.