It wasn't Sambo's like many think. It was Danny's Doughnuts.
From wikipedia regarding Denny's racist reputation.
"Racial discrimination lawsuits
During the 1990s, Denny's was involved in a series of discrimination lawsuits involving several cases of servers denying or providing inferior service to racial minorities, especially black customers.
In 1994, Denny's settled a class action lawsuit filed by thousands of black customers who had been refused service, forced to wait longer, or pay more than white customers. The $54.4 million settlement was the largest and broadest under federal public-accommodations laws established thirty years previously to end segregation in restaurants and public spaces.
These are some of the most notable incidents involving racial discrimination at Denny's, all occurring after the settlement:
A black Denny's customer was told, in 1995, that he and his friends had to pay up front at the counter upon ordering their meals. He questioned the waitress: "We asked the waitress about it and she said some black guys had been in earlier who made a scene and walked out without paying their bill. So the manager now wanted all blacks to pay up front."
Another 1993 incident occurred when six black United States Secret Service agents visited a Denny’s restaurant in Annapolis, Maryland. They were forced to wait an hour for service while their white companions were seated immediately upon entering.
In San Jose, California, in 1994, several black teenagers were refused service unless they agreed to pay in advance.
In 1997, six Asian-American students from Syracuse University visited a local Denny’s restaurant late at night. They waited for more than half an hour as white patrons were regularly served, seated, and offered more helpings. They complained to management and to their server but were forced to leave the establishment by two security guards called by Denny’s management. Then, according to the students, a group of white men came out of Denny's and attacked them and shouted racial epithets. Several of the students were beaten into unconsciousness.
After the $54.4 million settlement, Denny's created a racial sensitivity training program for all employees. Denny's has also made efforts at improving its public relations image by featuring blacks in their commercials, including one featuring Sherman Hemsley and Isabel Sanford, both actors from the popular The Jeffersons television series. In 2001, Denny's was chosen by Fortune magazine as the "Best Company for Minorities." In 2006 and 2007, Denny's topped Black Enterprise's "Best 40 Companies for Diversity.""
"The laws which forbid men to bear arms … only disarm those who are neither inclined nor determined to commit crimes,” Cesare Beccaria, an Italian scholar, wrote in his 1764 treatise on the subject. “These laws make the victims of attack worse off and improve the position of the assailant.”