I have read that
Chumba Casino is the only social casino to offer both a virtual and real money casino experience on a single platform, legally inside the US, via Sweepstakes. With its exclusive dual currency design, players can play for fun using the virtual gold coin currency or play for real money using ?Sweeps Cash?. Players can obtain ?Sweeps Cash? in numerous ways.
I had a look at it, it's based on a FB app, What do you think?