Metalocalypse

"Metalocalypse is a Flash animated television series on Adult Swim created by Brendon Small and Tommy Blacha. It has been described as "Spinal Tap meets Scooby-Doo meets Norway." The series was originally pitched as Deathclock, but the name could not be used due to an existing trademark. The show and the main characters' band were then renamed Dethklok. The show's title was then extended to Death Clock Metalocalypse, although the starring band still retained the name Dethklok. The crew finally shortened the title to Metalocalypse because the extended show title was too complicated." Read more here.

Is really good, specially for metal fans. You can find some of the episodes here, in YouTube.