Felicia Day
In Dr. Horrible's Sing Along Blog, Penny is played by Felicia Day. Felicia is one of the main characters in the
Guild. In the guild she is a cyber dork. She was also in
Buffy the Vampire Slayer. As well as staring in shows she has also been in an episode of
Monk,
House MD and has appeared in many Sears commercials. And she is in the movie
Red coming out later in 2010.