T he steady hum of slot machines is joined by a chorus of hymns every weekend at Riverside Resort and Casino in Laughlin, Nevada. Inside the 800-seat Don’s Celebrity Theatre, just past the poker tables, rows of chairs fill up not for a lounge singer, but for Catholic Mass . “We sometimes joke that we’re the only Catholic church that has valet parking,” Father Charlie Urnick, the longtime pastor of St. John the Baptist Parish, told The Independent. What began more than three decades ago as a temporary response to the lack of a dedicated parish church has become one of the country’s most unusual parish arrangements. In 1992, about 500 residents petitioned the Diocese of Reno to send a priest to the small river town, a little over 90 minutes from the Las Vegas Strip. Father John McShane began celebrating Mass in local casinos that same year. As the congregation grew, services moved in 1996 to the Riverside showroom, where they have continued ever since.…