The hotel call bell employed by Anthony of the Opie and Anthony show on XM Satellite Radio channel 202. When an overly racist or lewd comment is uttered, one of Anthony's many jobs is to ring the bell, thereby signifying that at least in one of the host's minds, a line has been crossed.
Opie: "Freaknik is like spring break for black people."
Jimmy: "Except they don't have to worry about going back to that pesky college."
Anthony: *ding* *ding* *ding* (ringing of inappropriate bell, laughter ensues)