Two words: Vegas baby! Actually gambling was not legal in the state of Nevada until 1931. Now days casinos are run by large corporations but in the late 40s it was the mafia that built the place now known as "sin city." Anything goes at Nevada casinos and most places offer drinks for free. You must be 21 years of age to gamble or consume alcohol on casino property.
Gambling at online casinos is not legal in all countries and locations. It is important that you check your local laws and regulations prior to gambling at these casinos.