Happy Days. Fonzie was originally fifth-billed on the cast of "Happy Days", but as he grew in popularity he increasingly became the center of the show.

One Tree Hill. One Tree Hill once did a school shooting episode.

Leroy Jethro Gibbs. Mark Harmon stars as Leroy Jethro Gibbs on "NCIS".

Cerebral Palsy. RJ Mitte, who plays Walter Jr. on "Breaking Bad", is the spokesperson for Inclusion in the Arts and Media of Performers With Disabilities (I AM PWD).

John Mayer. In the second season of "Chappelle's Show", John Mayer returns in an episode which features his guitar playing.

Massive Genius. Michael Imperioli plays Christopher on "The Sopranos".