: Phineas and Ferb begin their summer by building a logic-defying rollercoaster in their backyard, setting the "big project" template for the series.
In the pilot episode of Phineas and Ferb , several "helpful" recurring features and tropes of the series are established: [S1E1] Rollercoaster/Candace Loses Her Head
(the second half of S1E1) specifically features the family celebrating Candace’s birthday at Mount Rushmore, where Phineas and Ferb attempt to carve her face into the mountain as a "helpful" gift, while Candace nearly loses her mind trying to expose them. : Phineas and Ferb begin their summer by
: Perry the Platypus sneaks off to his secret lair to receive a mission from Major Monogram, marking the first time he foils Dr. Doofensmirtz's "Inator." [S1E1] Rollercoaster/Candace Loses Her Head