From Wikipedia: Dr. Horrible’s Sing-Along Blog is a 2008 musical tragicomedy short film produced exclusively for Internet distribution. It tells the story of Dr. Horrible, an aspiringsupervillain; Captain Hammer, his nemesis; and Penny, their mutual love interest.

Cast

Dr. Horrible's Sing-Along Blog cast and crewDr. Horrible’s Sing-Along Blog cast and crew
  • Neil Patrick Harris as Billy/Dr. Horrible: An aspiring supervillain of the mad scientist variety with the catchphrase, “I’ve got a Ph.D in Horribleness.” He desires to become a member of Bad Horse’s Evil League of Evil and use his inventions to take over the world and enact social change for the betterment of humanity, whom he sees as ignorant to the problems of the world. His unintentionally humorous socio-political beliefs include the paradoxical idea ofautocratic anarchism. As Billy, he struggles to make a romantic connection with Penny.
  • Felicia Day as Penny: Dr. Horrible’s love interest, whom he sees at the coin laundromat. She is idealistic and generous and volunteers at a homeless shelter. Her optimism clashes vividly with Billy’s cynicism and misanthropy, and her benevolence with Captain Hammer’s narcissism.
  • Nathan Fillion as Captain Hammer: Dr. Horrible’s arch-nemesis. Hammer is a self-centered superhero possessing super-human strength and near-invulnerability, though he is clearly the antagonist. He enjoys harassing Dr. Horrible even when the situation does not warrant it.
  • Simon Helberg as Moist: Dr. Horrible’s friend, who has the underwhelming ability to dampen things. Dr. Horrible calls him “my evil moisture buddy.” It’s implied that he’s in the Henchmen’s Union, and he can be seen aiding Dr. Horrible in robbing a bank.

# And may I add it is awesome.  NPH is fantastic and Nathon Fillon is great as Captain Hammer.  So worth watching.