Al Capone made millions of dollars on illegal liquor. What finally sent him to prison, though? Income tax evasion. (Source)

Prohibition made Dr. Seuss. Well, kinda. While he was at Dartmouth College, he became editor-in-chief of their humor magazine. When he was caught throwing a party with (gasp) liquor, he was forced to take a pen name. That name? "Seuss," to which he later added "Doctor," because at that point, might as well. (Source)

The slang term "the real McCoy" has its origins with Prohibition. There was a bootlegger by the name of McCoy whose product was better than most. "Is this the real McCoy?" customers would ask. And then there was shooting, because this was the '20s. (Source)

There were between 20,000 and 100,000 speakeasies (illegal bars) operating in New York during Prohibition. (Source)