Rollercoaster (Phineas and Ferb)

"Rollercoaster" is the series premiere of the American animated musical-comedy television series Phineas and Ferb, as well as the first half of the first episode of the series. The episode was originally broadcast on Disney Channel in the United States on August 17, 2007, as a preview of the series. The episode follows the series' protagonists, Phineas and Ferb, as they build an extremely large roller coaster starting in their backyard and going throughout the city. In a subplot, the protagonists' pet platypus Perry is a "secret agent" codenamed Agent P who is assigned the mission to investigate the plans of an evil but silly scientist named Dr. Heinz Doofenshmirtz.

Series' creators Dan Povenmire and Jeff "Swampy" Marsh wrote "Rollercoaster", the former of whom also directed the episode. The two used the episode to pitch the series to Disney. They recorded a set of storyboard reels, which Povenmire voiced over and sent them overseas. When originally aired on August 17, 2007, "Rollercoaster" peaked high ratings in several categories, leading to the episode being the second highest-rated telecast Disney Channel received in its recorded history. The preview garnered a recorded amount of 10.8 million viewers. In 2011, a half-hour musical episode titled "Rollercoaster: The Musical!" was released for the second season, which reenacts the events of "Rollercoaster" in musical form.