Sin to Win Weekend was mentioned in one of the episodes of CBS' Criminal Minds (Season 5, Episode 20: A Thousand Words).
It also comes from a book title, Sin to Win: Seven Deadly Steps to Success - which discusses of using the seven deadly sins as a stepping stone to success.
When used in the context of Atlantic City, it means that one is planning to go to casino heavy Atlantic City, often like Las Vegas referred to as Sin City, committing some sins, and coming home after the weekend having won money from gambling.
In 2009, EA Games held a "Sin to Win" contest to promote its upcoming game (released in February 2010) based on "Dante's Inferno".
Watch full episodes of Criminal Minds, view video clips and browse photos on CBS.com.