Credit: Cindy Ord/Getty Images; Donna Ward/Getty Images.

Is this what billionaires do for fun? Donald Trump, the real estate mogul who is worth $3.1 billion according to Forbes, is suing Bill Maher for $5 million for likening him to a monkey.

Trump called into "Fox & Friends" Monday to say that he's suing the HBO host for going on Jay Leno's "Tonight Show" last month and joking that Trump must be "the spawn of his mother having sex with an orangutan."