It has been my understanding that if you are a U.S. citizen, every dollar you acquire, by whatever means, onshore or offshore, is reportable and taxable as income excluding only certain tax-deferred investments and profits from real estate sales up to a cap.
So, it's not illegal to have an offshore accout; it's illegal to have one and fail to report your interest income. If you go to Monaco and win $1M, that's not illegal, but you must report it when you file your taxes. The local government will take their pound of flesh at the point of payment; reporting to the IRS is your job.
Now, you could always return via Grand Cayman, land in the U.S. sans capital, and leave some unnamed bank in Grand Cayman with a hefty new, numbered interest-earning account, but -- technically, at least -- you still have to report everything. Some things are nearly impossible for then to discover if you DON'T report them, BUT, if you don't report them and they DO discover them...you're TOAST.
But, then, I think you implied that you're somewhat of a gambler... ;-)
Pretty much what HKMk23 wrote. Your winnings are taxable, but you can write off your losses. IRS has no way of knowing what your losses are. Unless you get audited, you can show what ever losses you need to (I am NOT advocating committing fraud here.) You need to keep records of your losses or the IRS won't accept them under audit.
By the way, all this Bill does is limit the way one funds their account and cashes winnings.
IIRC, that's how the Kenedys and Soros manage to have huge amounts of money available, but don't actually pay taxes on it. Sort of like a consumption tax. They don't pay taxes on it until they actually use it.
Mark