Penn National Gaming Inc. bought Rocket Games Inc., a San Franciso developer of social casino games, for $60 million in cash, plus potential incentive payments to certain Rocket executives over the next two years, the Wyomissing, Pa., casino operator said Wednesday.

Among Rocket's 50 social casino games is Viva Slots Vegas, which has an audience of more than 200,000 daily players, according to Penn National, whose Penn Interactive Ventures is based in Conshohocken and operates,, and

Rocket, which will remain in San Francisco, had $5.6 million in operating earnings in the six months ended June 30. Penn National said it expected Rocket to immediately add to its earnings.

Pennsylvania came close to legalizing online gambling as part of the state budget passed last month. The effort could be revived in the fall.

Penn National operated 27 facilities in 17 jurisdictions, with 33,400 gaming machines, 800 table games, and 4,600 hotel rooms, as of June 30.