Phineas and Ferb - Season 2 Episode 61
The Doof Side of the Moon

Phineas and Ferb plan to put Danville on the map by building the worlds tallest building. However, Candace teams up with Albert and utilizes his expertise to bust her brothers. Meanwhile, Dr. Doofenshmirtz wants to be responsible for all the evil in the Tri-State Area, and since he believes that evil levels rise during a full moon, he plans to rotate it so that only the infamous "dark side of the moon" faces Earth.