Johnny Bravo is named after his creator, Giovanni "Johnny" Bravo Partible
Bart Simpson was given his middle name by his voice actor Nancy Cartwright. In one episode, Bart said "Or my name isn't Bartholomew J. Simpson!". When Matt Groening asked what the J stood for, she said "JoJo".
Neil Patrick Harris loves Red Bull and has a free lifetime supply because of the advertising he gives them when he drinks it on shows