List of Perry's entrances to his lair

A running gag in Phineas and Ferb is that when Agent P enters his lair in some sort of way.

Rollercoaster
Perry enters through a secret door on the side of the house.

Lawn Gnome Beach Party of Terror
Perry opens the top of a decorative mushroom in the backyard. When he reaches the bottom, he steps to his right and his fedora drops onto his head from a different tube.

Flop Starz
Perry flushes himself down a toilet and swims to his lair.

The Fast and the Phineas
Entered from the side of the house, followed by a ride down a tube elevator (Exactly the same way as in "Rollercoaster".).

Lights, Candace, Action!
None.

Raging Bully
At the mall, there is a Drink It soda machine that scans his foot, and leads to a slide that takes Perry to his lair.

Candace Loses Her Head
By a trash bin at Mount Rushmore and a lengthy travel tube ride. His trip is delayed for a few seconds to let Agent R go first through an intersection in the travel tube. (Perry returns to Mount Rushmore by exiting through the door on the side of the house and hops into a nearby bush to re-enter the travel tube.)

I, Brobot
Perry takes the "Chimney-vator" (an elevator inside the chimney of the boys' house) to get to his lair. Santa Claus also uses the Chimney-vator with Perry. Santa and Perry look at each other causing Perry to grin.

Run Away Runway
Perry makes sure Candace is gone, then sits on firewood in the fireplace, presses a button, and whizzes off to his lair.

The Magnificent Few
Enters a water trough at the dude ranch and swims underwater back to his lair, avoiding a shark with a laser beam strapped to its head.

S'Winter
Perry steps into a coil of hose and turns on the faucet, which sends him into a tube.

Jerk De Soleil
Perry (with his costume on) takes an elevator hidden in the lawn. When he gets to his headquarters and Major Monogram sees his costume, he laughs, takes a picture, and goes to email it to Carl.

Toy to the World
Perry goes over a wall of fasteners in the hardware store and pulls on a bag in the display. The display turns around and Perry is in his lair with his fedora on.

Get That Bigfoot Outa My Face!
Perry entered his lair through a very old tree slide. At the end of it he nearly knocks over a vase holding a flower.

Tree to Get Ready
None.

It's a Mud, Mud, Mud, Mud World
Perry enters through the couch.

The Ballad of Badbeard
Agent E grabs him by the shoulders and flies him to her nest where an egg hatches and a communicator communicating with Major Monogram is inside.

Mom's Birthday
Perry spins a photo of himself on the wall to go through a secret small door behind it to his lair.

Journey to the Center of Candace
He uses a keypad to activate a rotating section of the fence, which flings him through a trap door in the lawn.

It's About Time!
He enters in a photo booth at the museum.

Dude, We're Getting the Band Back Together
None.

Greece Lightning
Perry does not enter his lair. Instead, Major Monogram shows up in the museum inside of a replica of the Discobolos statue. It is a replica because the original doesn't have any clothes on and the version in this museum has a skirt.

Leave the Busting to Us!
Perry jumps into the bathtub, turning on the shower and appearing in his lair in through a bat of steam wearing a towel.

Crack That Whip
Perry puts himself inside a box and is sent by airmail to another country, where he is sent back to Danville by airmail and a mailman drops the box inside a mailbox, which leads to Perry's lair. "You do know we have an elevator, right?" Major Monogram points out.

The Best Lazy Day Ever
He took a tunnel hidden in the trash.

Boyfriend From 27,000 B.C.
Perry scuttles up a storm drain and pops out in mid-dressing of a magpie costume, then walks onto a power line scaring off some magpies, and hops into an emergency phone on the phone line pole, ending up falling from the ceiling of his lair landing into his chair.

Voyage to the Bottom of Buford
Perry surfs on a surfboard into a tube.

Road Trip
Perry inflates a replacement Perry, goes to back of RV and the wall flips into secret compartment for briefing.

Skiddley Whiffers
Perry walks into a music room. He plays a few notes of his theme song on a bass, opening a hatch under an amplifier. Perry falls through the hatch into a decorated lair, celebrating his 999th lair entrance, then Carl gives him a t-shirt with his (Carl's) face on it, Monogram tells to Perry to wear it because it is good for Carl's self-esteem.

Bullseye!
He uses a remote to open a narrow panel in the side of the house, rolls into it, and lands in his seat in his lair.

That's the Spirit
He enters in a jack-o'-lantern while wearing his Igor costume.

Agent Doof
He twists a board on the fence, turning it into a diving board. Then he dives into a baby pool, and the water floods into the lair, along with him.

Sleepwalk Surprise
Sits on a recliner and falls into his lair.

Doofapus
He rides a tricycle and enters to the underground parking lot and later an elevator to his lair.

When Worlds Collide
Sleeping in the lawn chair, Perry instantly gets a call and the head rest pulls down, rolling him through some croquet hoops hitting the stake, where he drops down into his lair.

Phineas and Ferb The Movie: Across the 2nd Dimension
A tube behind a painting, he lifts it and gets sucked in, Perry ends up being in a tube elevator and riding down to his lair, he sees and salutes Pinky, a lot of old agents are seen too. Phineas and Ferb use that exact same entrance later in the movie, and at the last scene, Perry is seen going down the elevator.