Gordon Randall Garrett's "... Or Your Money Back" (novelette, humor, free): Goodluck charms aren't illegal at roulette table!
Lot of smiles & giggles, after a modest start - particularly during the courtroom drama in later half.
Drawbacks of the story are completely irrelevant last para that extends the story to Mars exploration, & utterly lame explanations of the curious gadget that is at the heart of the story. The gadget & your thoughts together can, wirelessly, "cause minute, but significant, changes in the velocities of small, moving objects" - e.g., the outcome of certain gambling machines, including roulette wheel the story uses. It would have been far more fun if the gadget, functioning in ways beyond human comprehension, had arrived from a magical source - the way it often happens in Kuttner/Moore stories.
Story summary.Jason Howley, an inventor, has arrived somewhere in Neveda from New York City - both in US. Gambling is legal in former, illegal in later. He has come here to gamble - as a way of attracting world's attention to the "psionic" "science".
The plan is to use his curious gadget at a prominent local gambling joint to effect big wins. Idea is to attract attention, get caught by cops, get even more attention during the court trial, & come out scot free because no one can even begin to figure out how the gadget can influence the wheel. In this endeavor, he will enlist support of a competent unnamed narrator & local lawyer who will manage the legal end of drama.
He uses the gadget openly at the roulette wheel in Golden Casino. Quickly converts his $50 into $3,00,000! Attracts attention of the establishment's goons & cops. Gets arrested. And we are treated to good fun during defense. Of course, he gets away scot free - how can the court declare a gadget that works like a good luck charm illegal?
Fact sheet.First published: Astounding Science Fiction, September 1959.
Added to the list of stories from Campbell's Astounding.
Download full text from Project Gutenberg; cellphone versions from Manybooks.