Phineas and Ferb - Season 3 Episode 14
Phineas and Ferb Interrupted

When Mom tells Candace she wants to spend the day with her, Candace spends the entire time with her in the backyard so that she can bust her brothers. Unfortunately, Phineas and Ferbs grand plan for the day only entail watching the grass grow after getting zapped by Dr. Doofenshmirtzs Dull-and-Boring-inator earlier that day. Meanwhile, Agent P partners up with Dr. Doofenshmirtz to fix the now destroyed Dull-and-Boring-inator into a Dynamic-inator in order to fix Phineas and Ferb.