online poker would have been my suggestion, but oh no! the stupid government had to pass a law in the US to disallow any american to play with real money becuase it was considered "gambling", oh but they still keep those state lotteries which are gambling too, hypocritical basturds :cuss:
So instead, I would suggest you goto Gamecolony.com, Worldwinner, Moneygamming, etc. THese are sites where you can bet real money on a skill based game such as chess, checkers, backgammon, gin rummy, etc. And it is 100% legal in the US (skill games dont equal gambling). You can actually make lots of money if you are good. And its far easier to get good at this than in poker or sportsbetting; so its far more promising in terms of payout.
Its probably the best "gambling" option you have available if you live in the US.