James shares a wonderful story about a convention of physicists.
I believe the reference to the roulette wheel was from the early chaos theorists when they were young and ridiculous students, which I read about in James Gleik's book Chaos. The method of beating the wheel involved timing exactly when a point on the wheel passed a marker, feeding that information into a computer by way of moving one's toes in a shoe, and placing a bet on the basis of the result. There are 38 slots, and the timing allows a skilled practitioner to eliminate about 30% of the wheel where he knows it will not land. This is sufficient to beat the house over time. The odds of roulette are terrible, but not that terrible.
As for poker, one plays against others with the house taking its cut, so the odds are different. I have a son who consistently wins in poker in Las Vegas. He is an accountant and has a good sense for the odds, but the strength of his strategy is different. He is mindful of the admonition "If you can't figure out who the pigeon is after a few hands, you're the pigeon." He knows there are tables where the others can read him better than he them and wants to avoid those. He scouts out the various tables in the afternoon, trying to get a sense of which ones are at his level. He does not touch a drop of alcohol. He goes back to his room and takes a nap late in the afternoon, getting up to take a light supper. When he settles on a table, he only needs to stay about even at first. He still doesn't drink. After about two hours, a couple of others have started losing money and have had too much to drink. They start betting foolishly and playing foolishly in an effort to make their money back. Eventually, he takes their money.
It is not infallible. He figures that he loses his stake (it used to be $500 but that may be just what he tells his father, who finds risking that amount of money risky and intolerable. I would bet it's $1000 now) about one out of five trips. More often, he wins $1500-2000 over the weekend, enough to pay for his trip plus some extra. Very occasionally he will win well into the thousands.