Raj: Sheldon, what did Amy have that attracted you?
Sheldon: Oh, so many things. Her mind, her kindness, and especially her body.
Raj: Really?
Amy: Relax. We're the same blood type. He knew he could harvest an organ.

Sheldon: Who's ready to laugh? [Leonard groans] Okay. So Feynman, Einstein and Schrodinger walk into a bar. Feynman says, "It appears we're inside a joke." Einstein replies, "But only to an observer who saw us walk in simultaneously." To which Schrodinger says, "If someone's looking in the window, I'm leaving."
Leonard: [chuckles] That's actually funny.
Raj: You should send that to Jimmy Fallon.

Sheldon: Hello, I'm Dr. Sheldon Cooper.
Amy: And I'm Dr. Amy Farrah Fowler.
Sheldon: And welcome to a special retrospective, where we will take a look back at the history of Fun with Flags on an episode we're calling,
Both: "Fun with Flags - Behind the Flags: A Retrospective."

Howard: Should we get lunch or you want to eat at the zoo?
*Bernadette and Stuart staring at their phones*
Howard: (imitating Bernadette):"Oh, Howie, I don't need food as long as I can look at my phone."
Bernadette: I don't like when you imitate me.
Howard: You want to hear my Stuart? (imitating Stuart) "It's been a while since I've gone on a date.
You mind if we watch the monkeys doing it?"
Stuart: I said that to you in confidence.

Howard: How about after this we go see the exotic bird show?
Stuart: Not a good idea. My hair is a coveted nesting material.

Howard: Learning anything?
Bernadette: Well, sloth babies cling to their mothers' bodies for almost a year. I'm going back to work after only four months. So, I've learned I hate myself, I hate sloths, and I hate you for bringing me here.

Howard: What are you making?
Stuart: Chicken. Birds mess with my hair, I come back hard.

Penny: So, Bert, you were telling us how you updated your profile?
Bert: Right. I wasn't getting any responses, and then I added, "Recent $625,000 MacArthur grant winner", and five minutes later, I met my soul mate.
*Amy goes to the hallway*
Amy: I was wrong. You can come back in.

Raj: I'd love a personal trainer. I haven't seen my abs since they opened a Shake Shack on my drive home.

Howard: What are you doing here?
Stuart: Can't a guy hang out at a college he doesn't go to and stare at a baby that isn't his?

Amy: What are you looking at?
Sheldon: Comments from our Behind the Flags retrospective. Get this, people are calling it "the longest one yet".

Bert: Sorry again for barging in.
Leonard: You don't have to go. You're welcome to hang with us.
Sheldon: Actually, our friendship group is at capacity. But if anybody drops out, you're at the top of the list. Unless it's Raj, in which case, we'll probably get a person of color.

Sheldon: Where's Howard?
Raj: He took the day off.
Sheldon: Oh, let's take advantage of his absence and tell the kinds of jokes only physicists get. I'll go first.
Okay, here. Uh, Heisenberg is pulled over by a police officer. And the policeman says, "Did you know you were going 85 miles per hour?" And Heisenberg says, "Darn it, now I don't know where I am."

(Howard and Raj sing while playing the keyboards and guitar, respectively)
Howard: Wondering how it all began?
Raj: You'll need a good attention span-
Howard: For information and entertainment-
Raj: That's equally effective-
Both: It's Fun with Flags - Behind the Flags: A Retrospective. Flags!

Amy: Now, I'm sure many of you are wondering how Fun with Flags began.
Sheldon: So let's hear from some people who were there at the very start. Howard, flashback sounds.
Amy: Could have played that on my harp.
Sheldon: Just roll the clip.