Big Ideas

The Big Ideas were inventions created by Phineas Flynn and Ferb Fletcher almost every day during their summer vacation. Some of these items were used as a way of helping someone in need, while others were just to help them have the best possible summer ever. The phrase "Big Ideas" references the advertising campaign that Disney Channel ran prior to the launch of Phineas and Ferb series in February 2008. For Phineas, it was "he thinks big". For Ferb, it was "he thinks how".

The plans the boys came up with could be described as impossible because they were accomplished in a very short amount of time (less than a morning {they used the invention in the afternoon, most likely}) and involved technology that have yet to exist in the real world: teleportation, mind-switching, time traveling... Phineas and Ferb did not think of their plans as impossible, just fun and great. When Isabella Garcia-Shapiro asked Phineas if building a time machine was "kind of impossible", he replied, "That's a possibility".

Despite Phineas saying that he liked to "keep moving forward", he actually had repeated his big ideas. Examples are the rollercoaster, the waterslide, the molecular seperator and the time machine.

Phineas and Ferb were busted five times on-screen.
 * It was all Candace's dream in Perry the Platypus's dream.
 * Older Candace Flynn busted them while building the Rollercoaster, which had been undone by herself after she saw that this would lead to a dystopian society run by Emperor Heinz Doofenshmirtz. This happened in another universe. Later, Candace busted them by showing herself to future mom, but this had probably been undone by Isabella when she went back in time and made the entire episode undone during the credits. Along with the fifth time they were busted, this happened in another universe.
 * When they built a pioneer village, but that was undone when the Doofenshmirtz's acceleratorinator moved time backwards.
 * Once Candace succeeded in busting them briefly, however her mother was hit with Doof's "Forget-About-It-Inator" repeatedly and by the time she was no longer being hit by the ray, Candace had ran off and the boy's invention wasn't in view so she returned inside.
 * Linda Flynn-Fletcher "busted" Phineas and Ferb herself due to them leaving towels all over the ground.

However, there are other times where Phineas and Ferb's plots had been seen by their parents, however they weren't "busted" for them (assuming "busting" implies that they were intentioned to get in trouble for whatever they're doing). Their dad had also seen and had been involved in some of their big ideas, but it didn't seem he minded and Candace almost never got her dad to bust them which implied the busting power was from their mom.
 * One famous example is during Mom's birthday, because on that day she saw everything they built.
 * Their Mom actually saw Nosebud and said that it was "pretty cool" because it actually floated, but did not know about the station under it.
 * Mom saw the animal translator, only to her Phineas and Ferb were just using some sort of recording machine because it didn't work on Perry.
 * Mom saw only the top portion of the fort (and not the other giant parts of it). Upon seeing this, she remarked on how Phineas and Ferb were "beginning to take an interest in building things".
 * Mom saw Phineas and Ferb's creation, only Phineas and Ferb were gone and she thought it was some kind of modern art.

Also, there were other times where the plots were seen by Phineas and Ferb's parents, a good example being in "The Best Lazy Day Ever", however Candace built a dinosaur slide in that episode.
 * They built something in "Perry Lays an Egg", but Candace was the one who got in trouble.
 * Phineas and Ferb built a Latest Technology All-Terrain Vehicle but it was Candace who got into trouble as she said that she drove it herself and Mom shouted at her that she drove a car without any adult surveillance.
 * Phineas and Ferb didn't do anything in "Candace Gets Busted". But when Mom and Dad saw that Candace was having a party (the Intimate Get Together), Candace was the person busted.

Lawrence Fletcher had seen many of Phineas and Ferb's creations, but hadn't busted them.