The Sands Hotel was a famous hotel and casino in Las Vegas on Earth that was in operation from 1952 to 1996. It was best known for hosting shows featuring famous entertainers and singers, including Frank Sinatra and Dean Martin.
Vic Fontaine played at the Sands in 1958 with Lola Chrystal. While there, he met Sinatra and Martin and the three began playing blackjack. The trio would later lose several thousand dollars. (DS9 episode: "His Way", Star Trek Encyclopedia)
Others who were at the Sands at that time were The Righteous Brothers, Ronnie Gaylord & Burt Holiday, Betsy Duncan and Ernie Stewart. (Star Trek Encyclopedia)
In 2375, when Felix's jack-in-the-box was activated, Vic tried to get a gig at the Sands, although they would not return his calls. (DS9 episode: "Badda-Bing, Badda-Bang")
Several weeks later, Vic was going to the Sands with Ginger to see Jimmy Durante and Peter Lawford perform. (DS9 episode & novelization: "What You Leave Behind")