One of my favorite Samurai Jack episodes is "Episode XXVIII". It is included on the just-released season three set. The dvd description reads as: "When a man's daughter is kidnapped by Aku's children, Jack must infiltrate a rave to stop the musical brainwashing."
The art design of this series is spectacular! I especially love the work on this episode. The main part of the story happens at a rave, so there is a nice rythmic bass beat throughout the story. I've posted screenshots of the episode to illustrate the great artwork that goes into these episodes! Very nice!